The United States began a new round of attacks against multiple targets in Iran overnight, the US Army reported on Wednesday, hours after President Donald Trump promised new attacks if there was no peace agreement. Iran's joint military high command announced on Thursday (local time) the closure of the Strait of Hormuz, preventing the transit of ships including oil tankers and commercial ships, saying that any vessel that tries to pass through will be fired upon. "The attacks are a response to Iran's unjustified and continued aggression," the Armed Forces Central Command said in a post on the social network X, adding that the attacks began at 00:45 in Tehran. Related news: Iran responds to US retaliation and hits US bases. The attacks are the latest development in an escalation of assaults that threaten to reignite a full-scale war that broke off in early April when the two sides agreed to a fragile ceasefire. An explosion was heard in the port city of Sirik, and air defenses were activated in western Tehran, Iranian news agency Mehr reported. Trump had earlier told reporters on Wednesday at the White House: "We're going to hit them, hit them very hard." U.S. Defense Secretary Pete Hegseth later said during a visit to Central Command in Florida that the strikes "should advance our military interests and also strengthen our diplomatic position." "We will hit them hard tonight, and we hope Iran makes a good decision," he said. "If we need to negotiate with bombs, we will negotiate with bombs." The United States and Iran have exchanged fire several times since the provisional ceasefire came into effect, even with negotiators' frustrated attempts to end the three-month war. Trump has repeatedly stated that a deal is close, although there are no signs of significant progress, in addition to threatening to resume bombings. On Tuesday, the US military attacked air defense systems and radars around the Strait of Hormuz, after a US attack helicopter was shot down near the strategic waterway on Monday. Iran responded with missiles and drones to US bases in Jordan, Kuwait and Bahrain. A US official said there was no significant damage. Iran accused the US of attacking reservoirs that supplied 10 villages with drinking water and of violating international law. "This is not collateral damage -- it is a premeditated war crime and a flagrant violation of human rights," said Foreign Ministry spokesperson Esmaeil Baghei. The Pentagon did not immediately respond to a request for comment. Trump, who has previously threatened to destroy Iran's civilian infrastructure, did not say whether upcoming strikes would target power plants and bridges. In response, the head of the Iranian Parliament's National Security Commission, Ebrahim Azizi, warned that "the war will not be limited to the region." Despite belligerent language from both sides, there were signs of continued diplomatic efforts. A delegation from Qatar, which has been acting as a mediator between the United States and Iran, arrived in Tehran this Wednesday to discuss the latest developments, Iranian media reported. * Reporting by Menna Alaa El Din, Ahmed Tolba and Yomna Ehab * Reproduction of this content is prohibited