President Donald Trump warned Monday of a longer Iran war and refused to rule out ground troops, as his top diplomat suggested the timing of the US military operation was triggered by Israel.

Trump's brief remarks at the White House were his first in public since launching the strikes, after two Truth Social videos and a string of sometimes contradictory phone calls to media outlets.

Under relentless Israeli-US attack, Iran has bombarded US assets in the Gulf, but so far has not touched Turkey which would be a "high-cost strategic gamble" that could go disastrously wrong, analysts said.

Iran had long warned that if Washington attacked, it would target its regional assets -- which in principle should include NATO-member Turkey where US troops are stationed at several bases.

US President Donald Trump warned that his attack on Iran could run longer than a month, as Tehran retaliated to ongoing strikes by targeting US allies in the Gulf and drones hit the US embassy in Saudi Arabia on Tuesday.

Shortly after the United States urged Americans to flee all Middle Eastern nations from Egypt eastward, two drones hit the US embassy in Riyadh, sparking a quick vow by Trump to retaliate "soon", without elaborating how.

By Nidal al-Mughrabi and Pesha Magid

CAIRO/JERUSALEM, March 2 (Reuters) - Gaza is rapidly running out of its limited fuel supply and stocks of food staples may become tight, officials say, after Israel blocked the entry of fuel and goods into the war-shattered territory, citing fighting with Iran.

Israel's military closed all Gaza border crossings on Saturday after announcing air strikes on Iran carried out jointly with the United States. Israeli authorities say the crossings cannot be operated safely during war and have not said how long they would be shut.

By Ismet Mikailogullari

KAPIKOY, Turkey, March 2 (Reuters) - Hundreds of Iranians crossed the border into Turkey on Monday afternoon as the U.S.-Israeli war against Iran expanded, a Reuters witness said, with those arriving speaking of fear in Tehran and queues at petrol stations.

WASHINGTON, March 2 (Reuters) - U.S. Defense Secretary Pete Hegseth said on Monday that military operations against Iran would not lead to an "endless war" and that the aim was to destroy Tehran's missiles, Navy and other security infrastructure.

"We're hitting them surgically, overwhelmingly and unapologetically," Hegseth said during a press conference at the Pentagon.

(Reporting by Phil Stewart, Idrees Ali, Doina Chiacu; editing by Susan Heavey)

ASHGABAT, March 2 (Reuters) - Russia's embassy in Turkmenistan said on Monday that Russians unable to leave Iran could depart via Turkmenistan, a Central Asian former Soviet republic which shares a 1,148-kilometre (713-mile) border with northeastern Iran.

In a statement posted on Telegram, the embassy said Russians looking to leave via Turkmenistan could register with the Russian embassy in Tehran.

By Steven Scheer

JERUSALEM, March 2 (Reuters) - Israel's main international gateway, Ben Gurion Airport near Tel Aviv, said on its WhatsApp channel that it expects to reopen as early as Monday evening in an "extremely limited format" after the conflict with Iran shut Israeli airspace.

The airport said that starting on Tuesday, "flight operations will gradually expand depending on the security situation," although only Israeli carriers are expected to resume flights.

By Mushtaq Ali

PESHAWAR, March 2 (Reuters) - Pakistan sent the military into Himalayan Gilgit-Baltistan region on Monday and banned large gatherings nationwide after deadly protests against U.S. and Israeli strikes on Iran spread, with 26 dead so far.

In the northern city of Skardu, in Shi'ite majority Gilgit-Baltistan, normally a tourist hotspot, protesters set fire to a U.N. office on Sunday with 14 people, including a soldier, killed in the ensuing clashes, local officials said. Two others died in the capital Islamabad.

KYIV, March 2 (Reuters) - A new round of U.S.-brokered peace talks between Ukraine and Russia, scheduled for week, has not been canceled following the weekend strikes on Iran by the U.S. and Israel, Ukrainian President Volodymyr Zelenskiy said on Monday.

Zelenskiy said that Kyiv was considering a new location for the talks, which had been due to take place on March 5 and 6 in Abu Dhabi, and that Turkey or Switzerland were possibilities.