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.

The United States issued fresh charges over the attempted Tehran plot to kidnap and assassinate an Iranian-American journalist in New York, indicting an Iranian Revolutionary Guards Corps (IRGC) official among others in the case, according to a court document on Tuesday.

U.S. prosecutors have previously charged other suspects in the case, including one man in 2022 and two more in January 2023. Tuesday's filing did not name the alleged victim, but one of the previously charged suspects in the case was arrested for having a rifle outside the Brooklyn home of journalist and activist Masih Alinejad, Reuters reported.

"Today’s indictment exposes the full extent of Iran’s plot to silence an American journalist for criticizing the Iranian regime,” said U.S. Federal Bureau of Investigation Director Christopher Wray

The IRGC official, Ruhollah Bazghandi, was a brigadier general who previously served as chief of the corps' counterintelligence department, according to an indictment unsealed in federal court in Brooklyn.

Bazghandi was previously sanctioned by the U.S. Treasury Department. Prosecutors said that Bazghandi's internet activity, as well as that of three other individuals whose names were unsealed on Tuesday, pointed to their involvement in multiple assassination plots, read the report.

Bazghandi and the other newly charged defendants are based in Iran and remain at large, prosecutors said. The man arrested outside Alinejad's home, Khalid Mehdiyev, and another man allegedly involved in the plot, Rafat Amirov, are in U.S. custody and have pleaded not guilty to murder-for-hire charges.

Prosecutors have said that the defendants had plotted to lure Alinejad out of her house by asking her for flowers from her garden then gun her down.