At least one Israeli strike hit Beirut's southern suburbs early on Wednesday morning, Reuters witnesses said, hours after the U.S. said it opposed the scope of Israeli attacks in Beirut amid a rising death toll and fears of wider regional escalation.

Reuters witnesses heard two blasts and saw plumes of smoke emerging from two separate neighborhoods. It came after Israel issued an evacuation order early on Wednesday which mentioned only one building.

The Israeli military has in recent weeks carried out strikes on Beirut's southern suburbs, a Hezbollah stronghold, without advance warnings, or issued a warning for one area while striking more broadly.

The Israeli military said it conducted a strike on an underground Hezbollah weapons stockpile in the southern Beirut suburb of Dahiyeh.

"Prior to the strike, numerous steps were taken to mitigate the risk of harming civilians, including advancing warnings to the population in the area," the Israeli military said.

Israeli military evacuation orders were also affecting more than a quarter of Lebanon, according to the U.N. refugee agency, two weeks after Israel began incursions into the south of the country that it says are aimed at driving back Hezbollah.

Some Western countries have been pushing for a ceasefire between the two neighbors, as well as in Gaza, though the United States says it continues to support Israel and was sending an anti-missile system and troops.

On Tuesday, State Department spokesperson Matthew Miller said the U.S. had expressed its concerns to Prime Minister Benjamin Netanyahu's administration on the recent strikes.

"When it comes to the scope and nature of the bombing campaign that we saw in Beirut over the past few weeks, it's something that we made clear to the government of Israel we had concerns with and we were opposed to," he told reporters, adopting a harsher tone than Washington has taken so far.

The last time Beirut was hit was on Oct. 10, when two strikes near the city center killed 22 people and brought down entire buildings in a densely populated neighborhood.

The United States is "concerned" by reports of North Korean soldiers fighting for Russia in Ukraine, a White House spokesperson said on Tuesday.

Ukrainian President Volodymyr Zelenskiy this week accused North Korea of transferring personnel to Russia's armed forces, saying his intelligence agencies had briefed him on "the actual involvement of North Korea in the war" in Ukraine, Reuters reported.

The Kremlin has dismissed the allegation as "fake news."

White House National Security Council spokesperson Sean Savett said the involvement of North Korean troops in Ukraine, if true, would mark a significant increase in the North Korea-Russia defense relationship.

"Such a move would also indicate a new level of desperation for Russia as it continues to suffer significant casualties on the battlefield in its brutal war against Ukraine," Savett said in a statement.

Washington says North Korea has supplied Russia with ballistic missiles and ammunition. Moscow and Pyongyang have denied arms transfers but have vowed to boost military ties, possibly including joint drills, read the report.

The U.S. Army's Indo-Pacific commander, General Charles Flynn, told an event in Washington that North Korean personnel being involved in the conflict would allow Pyongyang to get real-time feedback on its weapons, something that had not been possible in the past.

"That's different because they are providing capabilities and – open source reporting – there's manpower that is also over there," he said at the Center for a New American Security.

"That kind of feedback from a real battlefield to North Korea to be able to make adjustments to their weapons, their ammunition, their capabilities, and even their people – to me, is very concerning," he said.

Russian President Vladimir Putin signed a treaty with North Korean leader Kim Jong Un when he visited Pyongyang in June, and said it included a mutual assistance clause under which each side agreed to help the other repel external aggression, Reuters reported.

The United States said on Sunday it will send U.S. troops to Israel along with an advanced U.S. anti-missile system, in a highly unusual deployment meant to bolster the country's air defenses following missile attacks by Iran.

U.S. President Joe Biden said the move was meant "to defend Israel," which is weighing an expected retaliation against Iran after Tehran fired more than 180 missiles at Israel on Oct 1, Reuters reported.

The United States has been privately urging Israel to calibrate its response to avoid triggering a broader war in the Middle East, officials say, with Biden publicly voicing his opposition to an Israeli attack on Iran's nuclear sites and his concerns about a strike on Iran's energy infrastructure.

Pentagon spokesperson Major General Patrick Ryder described the deployment as part of "the broader adjustments the U.S. military has made in recent months" to support Israel and defend U.S. personnel from attacks by Iran and Iranian-backed groups.

But a U.S. military deployment to Israel is rare outside of drills, given Israel's own military capabilities. U.S. troops in recent months have aided Israel's defense from warships and fighter jets in the Middle East when it came under Iranian attack.

But they were based outside of Israel.

The Terminal High Altitude Area Defense system, or THAAD, is a critical part of the U.S. military's layered air defense systems and adds to Israel's already formidable anti-missile defenses, Reuters reported.

A THAAD battery usually requires about 100 troops to operate. It counts six truck mounted launchers, with eight interceptors on each launcher, and a powerful radar.

Iran's Foreign Minister Abbas Araqchi warned earlier on Sunday that the United States was putting the lives of its troops "at risk by deploying them to operate U.S. missile systems in Israel."

"While we have made tremendous efforts in recent days to contain an all-out war in our region, I say it clearly that we have no red lines in defending our people and interests," Araqchi posted on X.

Still, experts say Iran has sought to avoid a direct war with the United States, making deployment of U.S. forces to Israel another factor in its calculus going forward.

Iran launched missiles and drones at Israel in April. Then on Oct. 1, Iran fired more than 180 ballistic missiles at Israel amid another escalation in fighting between Israel and Iran-backed Hezbollah in Lebanon. Many were intercepted in flight but some penetrated missile defenses.

U.S. officials did not say how quickly the system would be deployed to Israel.

The Pentagon said a THAAD was deployed to southern Israel for drills in 2019, the last and only time it was known to be there.