Israel's Mossad spy agency planted explosives inside 5,000 pagers imported by Lebanese group Hezbollah months before Tuesday's detonations, a senior Lebanese security source and another source told Reuters.

The operation was an unprecedented Hezbollah security breach that saw thousands of pagers detonate across Lebanon, killing nine people and wounding nearly 3,000 others, including the group's fighters and Iran's envoy to Beirut.

The Lebanese security source said the pagers were from Taiwan-based Gold Apollo, but the company said in a statement it did not manufacture the devices. It said they were made by a company called BAC which has a licence to use its brand, but gave no more details.

Iran-backed Hezbollah has vowed to retaliate against Israel, whose military declined to comment on the blasts, Reuters reported.

Hezbollah said in a statement on Wednesday that "the resistance will continue today, like any other day, its operations to support Gaza, its people and its resistance which is a separate path from the harsh punishment that the criminal enemy (Israel) should await in response to Tuesday's massacre".

The plot appears to have been many months in the making, several sources told Reuters.

The senior Lebanese security source said the group had ordered 5,000 beepers from Gold Apollo, which several sources say were brought into the country earlier this year.

Gold Apollo founder Hsu Ching-Kuang said the pagers used in the explosion were made by a company in Europe that had the right to use the firm's brand, the name of which he could not immediately confirm. The company in a statement named BAC as the firm, but Hsu declined to comment on its location.

"The product was not ours. It was only that it had our brand on it," Hsu told reporters at the company's offices in the northern Taiwanese city of New Taipei on Wednesday.

The senior Lebanese security source identified a photograph of the model of the pager, an AP924, which like other pagers wirelessly receive and display text messages but cannot make telephone calls.

Gold Apollo said in a statement that the AR-924 model was produced and sold by BAC.

"We only provide brand trademark authorisation and have no involvement in the design or manufacturing of this product," the statement said.

Hezbollah fighters have been using pagers as a low-tech means of communication in an attempt to evade Israeli location-tracking, two sources familiar with the group's operations told Reuters this year.

But the senior Lebanese source said the devices had been modified by Israel's spy service "at the production level."

"The Mossad injected a board inside of the device that has explosive material that receives a code. It's very hard to detect it through any means. Even with any device or scanner," the source said.

The source said 3,000 of the pagers exploded when a coded message was sent to them, simultaneously activating the explosives.

Another security source told Reuters that up to three grams of explosives were hidden in the new pagers and had gone "undetected" by Hezbollah for months.

Hsu said he did not know how the pagers could have been rigged to explode.

Israeli officials did not immediately respond to Reuters requests for comment.

Images of destroyed pagers analysed by Reuters showed a format and stickers on the back that were consistent with pagers made by Gold Apollo.

Hezbollah was reeling from the attack, which left fighters and others bloodied, hospitalized or dead. One Hezbollah official, speaking on condition of anonymity, said the detonation was the group's "biggest security breach" since the Gaza conflict between Israel and Hezbollah ally Hamas erupted on Oct. 7.

"This would easily be the biggest counterintelligence failure that Hezbollah has had in decades," said Jonathan Panikoff, the U.S. government's former deputy national intelligence officer on the Middle East.

Break Your Phones

In February, Hezbollah drew up a war plan that aimed to address gaps in the group's intelligence infrastructure. 

Around 170 fighters had already been killed in targeted Israeli strikes on Lebanon, including one senior commander and a top Hamas official in Beirut.

In a televised speech on Feb. 13, the group's Secretary General Hassan Nasrallah sternly warned supporters that their phones were more dangerous than Israeli spies, saying they should break, bury or lock them in an iron box.

Instead, the group opted to distribute pagers to Hezbollah members across the group's various branches - from fighters to medics working in its relief services.

The explosions maimed many Hezbollah members, according to footage from hospitals reviewed by Reuters. Wounded men had injuries of varying degrees to the face, missing fingers and gaping wounds at the hip where the pagers were likely worn.

"We really got hit hard," said the senior Lebanese security source, who has direct knowledge of the group's probe into the explosions.

U.S. Democratic presidential candidate Kamala Harris called on Tuesday for an end to the Israel-Gaza war and said that Israel must not reoccupy the Palestinian enclave once the nearly year-old conflict comes to an end.

Speaking in Philadelphia to the National Association of Black Journalists, she called for a ceasefire between Israel and Palestinian Hamas militants, a two-state solution and Middle East stability in a way that does not empower Iran.

"We've made ourselves very clear this deal needs to get done in the best interest of everyone in the region," Harris, the U.S. vice president, said in response to questions asked by three journalists.

At least 41,252 people have been killed and 95,497 wounded in the Israeli offensive in the Hamas-ruled strip since Oct. 7, the Gaza health ministry said. The war began that day when Hamas attacked Israel, killing 1,200 people, mostly civilians, and taking about 250 hostages, according to Israeli tallies.

Harris was asked about Springfield, Ohio, a city that for days has found itself at the center of a social media maelstrom after right-wing agitators latched onto false claims that Haitian arrivals were eating household pets.

Former President Donald Trump, Harris' Republican rival in the Nov. 5 presidential election, has pledged to conduct mass deportations of Haitian immigrants from Springfield if elected, even though the majority are in the United States legally.

"This is exhausting and it's harmful and it's hateful and grounded in some age-old stuff that we should not have the tolerance for," Harris said.

The 45-minute interview began with economic issues. Harris said that if elected president she will work with private investors to boost housing supply, acknowledging that more work was needed to lower prices for Americans.

"One of the big issues that affects people right now in terms of the economy and their economic wellbeing is we have a shortage of housing supply," Harris said. "It's too expensive."

Harris reiterated a plan to expand the child tax credit to $6,000. She repeated a pledge that Americans not pay more than 7% of their income on childcare.

The interview was scheduled after Harris did not attend the group's convention in Chicago in July when Trump, in an interview, questioned her Black identity.

In the 2020 presidential election, Black voters supported then-candidate Joe Biden 92% to 8% over the then-incumbent Trump, according to the Pew Research Center. Most Black voters, 63%, plan to support Harris, compared with 13% for Trump, according to an NAACP survey released this month.

However, some Black voters are losing faith in the Democratic Party. Over one quarter of younger Black men say they would support Trump this election, the NAACP poll showed.

"Black men are like any other voting group," Harris said. "You gotta earn their vote."

The interview was conducted by NABJ members from TheGrio and Politico as well as an anchor for WHYY-FM, a public radio station.

Both Harris and Trump have made efforts to win over Black voters, whose support may be decisive in the closely fought Nov. 5 vote, especially in a handful of battleground states such as Pennsylvania and Georgia.

Some forecasters regard Pennsylvania as a must-win state.

In Georgia, an intense battle is being waged for the Black voters who make up a third of the state's population, the biggest proportion of Black voters in any of the seven battleground states.

Trump's attempt to pull in more support from Black voters is complicated by their traditional loyalty to the Democratic Party, his past racist remarks and a history of Republican-backed voting restrictions that activists say make it harder for Black residents to vote. Republicans deny trying to suppress the vote.

The outgoing head of NATO Jens Stoltenberg said on Monday he welcomed talks on Ukraine's use of long-range missiles to strike inside Russian territory, but any decision on the issue would have to be made by individual allies, Reuters reported.

Ukrainian President Volodymyr Zelenskiy has been pleading with allies for months to let Ukraine fire Western missiles including long-range U.S. ATACMS and British Storm Shadows deep into Russia to limit Moscow's ability to launch attacks.

British Prime Minister Keir Starmer and U.S. President Joe Biden held talks in Washington on Friday on whether to allow Kyiv to use the long-range missiles against targets in Russia. No decision was announced.

"I welcome these developments and these decisions but its for individual allies to make the final decisions," Stoltenberg told LBC radio. "Allies have different policies on this."

Some U.S. officials are deeply skeptical that allowing the use of such missiles would make a significant difference in Kyiv's battle against Russian invaders, read the report.

President Vladimir Putin has said the West would be directly fighting Russia if it allowed Ukraine to strike with Western-made long-range missiles.

Asked about possible Russian retaliation, Stoltenberg said there were "no risk-free options in the war".

"But I continue to believe that the biggest risk for us, for United Kingdom, for NATO, will be if President Putin wins in Ukraine," he added.