An Israeli strike killed at least three journalists and wounded several others as they slept in guesthouses in southern Lebanon on Friday, Lebanon's health ministry said, in what Beirut declared a war crime.

U.S. Secretary of State Antony Blinken said there was an urgency to get a diplomatic resolution to the conflict in Lebanon, a day after he said Washington did not want to see a protracted campaign there by its ally Israel, Reuters reported.

Israel launched its major offensive in Lebanon a month ago, saying it was targeting the heavily armed, Iran-backed Hezbollah to secure the return home of tens of thousands of Israelis evacuated from the north due to cross-border rocket attacks.

Beirut authorities say the offensive has killed more than 2,500 people and displaced more than 1.2 million people, the majority of them over the last month, creating a humanitarian crisis.

"We have a sense of real urgency in getting to a diplomatic resolution and the full implementation of UN Security Council Resolution 1701, such that there can be real security along border between Israel and Lebanon," Blinken said in London.

He said it was important so "people at both sides of the border can have the confidence to... return to their homes".

The journalists killed were camera operator Ghassan Najjar and engineer Mohamed Reda of the pro-Iranian news outlet Al-Mayadeen and camera operator Wissam Qassem, who worked for Hezbollah's Al-Manar, the outlets said in separate statements.

They had been staying in the southern town of Hasbaya when it was hit around 3 a.m. (midnight GMT). The town, inhabited by both Muslims and Christians, had not previously been targeted.

It was the deadliest attack on media in Lebanon since hostilities erupted between Israel and Hezbollah just over a year ago, prompted by the Gaza war.

There was no immediate comment from Israel, which in general denies deliberately attacking journalists.

The United States said for the first time on Wednesday that it had seen evidence that North Korea has sent 3,000 troops to Russia for possible deployment in Ukraine, a move that could mark a significant escalation in Russia's war against its neighbor.

U.S. Defense Secretary Lloyd Austin, speaking in Rome, said it would be "very, very serious" if the North Koreans were preparing to fight alongside Russia in Ukraine, as Kyiv has alleged. But he said it remained to be seen what they would be doing there, Reuters reported.

"There is evidence that there are DPRK troops in Russia," Austin told reporters, using North Korea's formal name, the Democratic People's Republic of Korea.

Speaking to reporters later on Wednesday White House spokesperson John Kirby said the United States believes at least 3,000 North Korean troops are undergoing training at three military bases in eastern Russia.

The U.S. determined the North Korean soldiers were transported by ship in early-to-mid October from North Korea's Wonsan region to the eastern Russian city of Vladivostok before being taken to three military training sites in eastern Russia, said Kirby.

"If they do deploy to fight against Ukraine, they're fair game," he said. "They're fair targets and the Ukrainian military will defend themselves against North Korean soldiers the same way they're defending themselves against Russian soldiers."

In Seoul, South Korean lawmakers said that Pyongyang had promised to provide a total of about 10,000 troops, whose deployment was expected to be completed by December, the lawmakers told reporters after being briefed by South Korea's national intelligence agency.

"Signs of troops being trained inside North Korea were detected in September and October," Park Sun-won, a member of a parliamentary intelligence committee, said after the briefing.

The Ukraine conflict broke out when Russia invaded its neighbor in February 2022 and has since developed into a war of attrition largely fought along front lines in eastern Ukraine, with huge numbers of casualties on both sides.

The United States said the alleged North Korean deployment could be further evidence that the Russian military was having problems with manpower.

The Kremlin has previously dismissed Seoul's claims about the North's troop deployment as "fake news" and a North Korean representative to the United Nations in New York called it "groundless rumors" at a meeting on Monday.

Both Moscow and Pyongyang have also denied weapons transfers, but they have pledged to boost military ties and signed a mutual defense treaty at a summit in June.

Israel's military said it had killed three Hezbollah commanders and some 70 fighters in southern Lebanon in the past 48 hours, a day after confirming it had killed Hashem Safieddine, the militant group's heir apparent leader.

"In southern Lebanon, IDF troops continue conducting limited, localized, targeted raids against Hezbollah terrorist infrastructure and operatives," the Israel Defense Force (IDF) said in a statement.

"Over the past day, the troops eliminated approximately 70 terrorists in ground and aerial strikes," it said.

Israel expanded its evacuation warnings to several central neighborhoods in the southern Lebanese port city of Tyre on Wednesday, ordering people to evacuate north out of the city, Reuters reported.

Israel has been carrying out an escalating offensive in Lebanon after a year of border clashes with Hezbollah, the most formidably armed of Iran's proxy forces across the Middle East.

Israel's offensive has driven at least 1.2 million Lebanese from their homes and killed 2,530 people, including at least 63 over the past 24 hours, the Lebanese government said on Tuesday.

On Tuesday, the IDF said it had confirmed the killing of Hashem Safieddine, the heir apparent to its leader Hassan Nasrallah who was killed in an Israeli attack last month.

The military said Safieddine was killed in a strike carried out three weeks ago in Beirut's southern suburbs, its first confirmation of his death. Earlier this month, Israel said he had probably been eliminated.

There was no immediate response from Hezbollah to Israel's statement that it had killed Safieddine.

Israel has so far shown no sign of relenting in its Gaza and Lebanon campaigns even after assassinating several leaders of Hamas and Hezbollah.