Iran and the United States appeared at an impasse, hardening their positions over ceasefire talks and setting the stage for another potential escalation in the Middle East war as thousands more U.S. troops neared the region. Meanwhile, President Donald Trump on Thursday extended his deadline for Iran to open the Strait of Hormuz to April 6, and Tehran tightened its grip on the crucial strait. Israel poured more troops into southern Lebanon to fight the Iran-backed militant group Hezbollah. Sirens over Israel warned of barrages of incoming Iranian missiles, and Gulf nations worked to intercept fire. Heavy strikes were reported in Iran's capital and other cities.

Airstrikes battered Iran and Iranian missiles and drones targeted Israel and sites across the Mideast. Those attacks came Tuesday after President Donald Trump said the United States was in talks with the Islamic Republic to end the war. With thousands more U.S. Marines on their way to the Gulf, both sides firing intense barrages and Iran denying any negotiations are taking place, the war's tempo remained high. A day earlier, Trump delayed his self-imposed deadline for Iran to reopen the Strait of Hormuz. Pakistan has offered to host diplomatic talks. But Iran remained defiant. The spokesman of its top military command said that the armed forces would fight "until complete victory."

Iran is threatening recreational and tourist sites worldwide and insisting it is still building missiles three weeks into an escalating war in the Middle East. The United States is deploying more warships and another 2,500 Marines to the region. As Israeli strikes landed in Tehran, Iran launched more attacks on Israel and energy sites in neighboring Gulf Arab states. With little information coming out of Iran, it was not clear how much damage its forces have suffered in the punishing U.S. and Israeli strikes that began Feb. 28 — or even who was truly in charge of the country. But Iran's attacks are still choking off oil supplies and denting the global economy.

Iran has intensified its attacks on oil and gas facilities around the Gulf, dramatically raising the stakes in a war that is sending shock waves through the global economy. Thursday's strikes came in retaliation for an Israeli attack on a key Iranian natural gas field. They sent fuel prices soaring and risked drawing Iran's Arab neighbors directly into the conflict. Tehran targeted energy production, further stressing global supplies already under pressure because of Iran's stranglehold on the Strait of Hormuz. That's a strategic waterway through which a fifth of the world's oil is transported. Israeli Prime Minister Benjamin Netanyahu says Iran no longer can enrich uranium or make ballistic missiles.

Fears of a global energy crisis persist as the war in the Middle East rages on. More U.S.-Israeli strikes hit the Iranian capital Monday and Israel again bombarded Lebanon. An Iranian drone strike temporarily shut Dubai's airport. That's a crucial global travel hub and the attack underscored the threats to the world economy. Since the United States and Israel attacked Iran more than two weeks ago, Tehran has regularly fired on Israel, American bases in the region, and Gulf Arab countries' energy infrastructure. It has also effectively stopped shipping traffic in the Strait of Hormuz. That has dramatically increased the price of oil and put pressure on Washington to do something to ease the pain consumers are feeling.

Iran's new supreme leader released his first statement since succeeding his late father. Ayatollah Mojtaba Khamenei said Thursday that Iran would keep up its attacks on its Gulf Arab neighbors and use the effective closure of the strategic Strait of Hormuz as leverage against the United States and Israel. Khamenei, 56, who Israel suspects was wounded in the opening salvo of the war, did not appear on camera, as his statement was read by a state TV news anchor. The statement included a vow to avenge those killed in the war, including in a strike on a school that killed over 165 people.