By Feras Dalatey , Timour Azhari, Laila Bassam and Mahmoud Hassano

DAMASCUS/BEIRUT, March 3 (Reuters) - Syria has reinforced its border with Lebanon with rocket units and thousands of troops, eight Syrian and Lebanese sources said on Tuesday, as conflict spread in the region including between Israel and Hezbollah in Lebanon.

The sources included five Syrian military officers, a Syrian security official and two Lebanese security officials who spoke on condition of anonymity.

The Pentagon's policy chief on Tuesday distanced the United States from the death of Iran's Supreme Leader Ayatollah Ali Khamenei, saying he was killed by an Israeli strike.

Testifying before the Senate Armed Services Committee, Elbridge Colby said the strike that killed Khamenei and other senior Iranian leaders was not part of the American military campaign.

"Those are Israeli operations," Colby said, pushing back when pressed by lawmakers about whether regime change was an objective of US action.

Iran's slain supreme leader Ayatollah Ali Khamenei will be buried in the holy city of Mashhad, the Fars news agency said Tuesday.

Khamenei, who led the country for 36 years, was killed at 86 during a wave of US-Israeli attacks on Saturday.

He was originally from Mashhad, Iran's second-largest city, where his father is buried at the Imam Reza shrine.

Before the burial, a "large farewell ceremony" will be held in Tehran, the Revolutionary Guards said on their Telegram account.

No date for the burial was disclosed.

By Andrew Osborn

MOSCOW, March 3 (Reuters) - When President Donald Trump returned to the White House last year, some Russian hardliners were cautiously optimistic, hoping his unpredictability and transactional nature might benefit Moscow on Ukraine.

But his attack on Iran means many now see him as a growing threat to Russia itself and are questioning if Trump is the pragmatic, potentially pro-Moscow strongman ready to deal in realpolitik that they thought he was.

By Ted Hesson, Susan Heavey and David Shepardson

WASHINGTON, March 3 (Reuters) - U.S. Homeland Security Secretary Kristi Noem during congressional testimony on Tuesday stood by her remarks calling the acts of two U.S. citizens shot dead by federal immigration officers in Minneapolis "domestic terrorism."

Noem, who is overseeing Republican President Donald Trump's immigration crackdown, was pressed about her statements by Democrats and some Republicansduring a Senate Judiciary Committee hearing.

By Federico Maccioni, Lucy Craymer and Rachna Uppal

DUBAI, March 3 (Reuters) - As Middle East tensions rise ever higher, tens of thousands of people are finding themselves stranded across the Gulf with few options for leaving a region suddenly engulfed by war.

March 3 (Reuters) - Here are statistics released by Gulf defence ministries on drones and missiles that Iran has fired at their territories since the start of the U.S.-Israeli air war against Iran:

UNITED ARAB EMIRATES:

Ballistic missiles:

Drones:

QATAR

Ballistic missiles:

Drones:

Iran's supreme leader Ali Khamenei's death is "historically significant" but will not "automatically" lead to the fall of the Iranian system, the widow of the country's last shah told AFP in an interview Tuesday.

"The passing of a man -- however central he may be to the architecture of power -- does not automatically mean the end of a system," said Farah Pahlavi, three days after US-Israeli strikes on Iran killed Khamenei.

KYIV, March 3 (Reuters) - Ukraine's President Volodymyr Zelenskiy discussed Iranian strikes with United Arab Emirates President Mohamed bin Zayed Al Nahyan and Qatar's Emir Sheikh Tamim bin Hamad al-Thani.

Ukraine has great expertise in countering drones and missiles, honed over four years facing waves of Russian attacks.

"We discussed how we can help in this situation and support the protection of lives. It was agreed that our teams will work on this," Zelenskiy said on X after a call with the UAE leader.

The Ukrainian leader expressed solidarity with both nations.

WASHINGTON, March 3 (Reuters) - President Donald Trump said on Tuesday that the U.S. military had been successful against many Iranian naval and air targets, saying "just about everything has been knocked out."

He made his comments in the Oval Office ahead of a meeting with German Chancellor Friedrich Merz.

Trump, answering questions from reporters, said he ordered the attack against Iran because "I had a feeling" that Iran would attack the United States as negotiations over its nuclear program stalled.