DUBAI/WASHINGTON - Israel and Iran attacked each other on Saturday as the U.S. was sending thousands more Marines to the Middle East and President Donald Trump accused NATO allies of cowardice over their reluctance to help open the Strait of Hormuz.

Israel also attacked Beirut, saying it was targeting Hezbollah as it steps up airstrikes targeting the Iran-backed Lebanese militia in the deadliest spillover from the war on Iran since Hezbollah fired on Israel in support of Tehran on March 2.

More than 2,000 people have been killed since the U.S. and Israel attacked Iran on February 28, while Americans appear increasingly concerned at signs the war could expand further as it enters its fourth week.

Vital energy infrastructure in Iran and neighbouring Gulf states has been attacked, sending oil prices up 50% and threatening global economic shock.

IRAN TARGETS U.S.-UK BASE IN INDIAN OCEAN

Israel said Saturday's attacks on Iran included Tehran, Karaj west of the capital and the central city of Isfahan.

Before its strikes on Lebanon, the Israeli military said, it issued evacuation warnings for seven neighborhoods in the southern suburbs of Beirut. More than 1,000 people have been killed in Lebanon and over 1 million displaced in the Israeli attacks.

Air raid sirens in Israel warned of incoming missiles from early morning, sending millions to shelters as the blasts of interceptions rang out from above. There were no immediate reports of casualties.

Israel's military said search and rescue teams were headed to impact sites in central Israel and asked the public to avoid gatherings in those areas. Iranian missile attacks have killed 19 people in Israel and the Palestinian territories since the war began.

Iran fired two ballistic missiles at the U.S.-British military base Diego Garcia in the Indian Ocean, demonstrating the reach of its weaponry, the semi-official Mehr news agency reported. The Wall Street Journal said two intermediate-range ballistic missiles were launched but did not hit the base.

Natural gas prices in Europe surged as much as 35% this week as Iran and Israel hit some of the region's most important gas infrastructure. The EU urged members to lower gas-storage targets and start refilling reserves gradually to curb demand, the Financial Times reported on Saturday.

United Airlines UAL.O said it would cut its scheduled flights by 5% in the second and third quarters, planning for prolonged higher oil prices.

The Strait of Hormuz, conduit for around a fifth of global oil and liquefied natural gas supplies, has been effectively closed to most shipping.

Trump on Friday called U.S. allies "cowards" for not helping open the strait.

Several allies, who were not consulted before the war, have pledged to join "appropriate efforts" to ensure safe passage through the strait, but Germany and France have said fighting must stop first. German Chancellor Friedrich Merz said he would speak to Trump this weekend.

STILL UNSEEN, KHAMENEI ISSUES DEFIANT MESSAGE

Iran is ready to let Japan-related vessels pass through the narrow waterway, Iranian Foreign Minister Abbas Araqchi told Kyodo news agency. Japan gets around 90% of its oil shipments via the strait.

The Trump White House, in an effort to increase supply and lower prices, said it would waive sanctions on Iranian oil for 30 days to allow the sale of 140 million barrels on tankers. The administration had previously eased sanctions on a similar amount of sanctioned Russian oil.

As Muslims celebrated Eid al-Fitr to end the fasting month of Ramadan and Iranians marked Nowruz, the Persian New Year, Iran's new Supreme Leader Ayatollah Mojtaba Khamenei issued a message of defiance.

Khamenei - who did not appear at Eid prayers and has not been seen in public since the initial Israeli attack that wounded him and killed his father, Ayatollah Ali Khamenei - said in his statement that Iranians had responded with unity and resistance and "dealt a disorienting blow to the enemy".

Amid Khamenei's long public absence, Israeli Prime Minister Benjamin Netanyahu told a press conference on Thursday: "I'm not sure who's running Iran right now. Mojtaba, the replacement Ayatollah, is not showing his face. Have you seen him? We haven't."

Three U.S. officials told Reuters on Friday that 2,500 Marines, along with the amphibious assault ship Boxer and accompanying warships, would deploy to the region, although they did not say what their role would be.

A new Reuters/Ipsos poll showed almost two-thirds of Americans believe Trump will order troops into a large-scale ground war, with only 7% supporting such a move.

Two officials said there had been no decision on whether to send troops into Iran. Sources had told Reuters that possible targets could include Iran's coast or Kharg Island oil export hub.

Trump said on Thursday he was "not putting troops anywhere", when asked about his plans, adding, "If I were, I certainly wouldn't tell you."

Maps and chart of the Iran War https://www.reuters.com/graphics/IRAN-CRISIS/MAPS/znpnmelervl/#attacks-on-major-oil-gas-sites-in-the-middle-east

-Reporting by Phil Stewart and Idrees Ali in Washington, Andrew Mills in Doha and Timour Azhari in Riyadh; Additional reporting by Reuters bureaus; Writing by Tom Hogue; Editing by William Mallard/Reuters