WASHINGTON - 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.
New powerful explosions shook windows in Tehran throughout the night as fighter jets flew over the Iranian capital, AFP journalists witnessed, and the Pentagon said it had achieved air superiority over the country, ruled since 1979 by Islamic clerics virulently opposed to the United States.
Beyond launching missile and drone attacks that forced Qatar's state-run energy firm to halt liquefied natural gas production, Tehran also vowed to choke one of the world's most vital shipping lanes.
"We will burn any ship that tries to pass through the Strait of Hormuz," Revolutionary Guards General Sardar Jabbari said of the strategic waterway to the Gulf through which about 20 percent of global seaborne oil travels.
Trump said that the war, which began Saturday with a strike that killed Iran's supreme leader, Ayatollah Ali Khamenei, was going "substantially" ahead of schedule but that the United States was equipped for a prolonged conflict.
"From the beginning we projected four to five weeks, but we have capability to go far longer than that," Trump said at the White House.
The US president laid out for the first time the operation's objectives -- destroying Iran's missiles, navy and nuclear programme and stopping its support for armed groups across the region. The goals notably did not include toppling the Islamic republic, even though on Saturday Trump had urged the people of Iran to rise up and overthrow their government.
As Iran ramped up its retaliation, Saudi Arabia, home to one of the region's largest oil refineries which has already been closed following an attack, said it intercepted eight more drones in two cities, including the capital, on Tuesday.
The Saudi defence ministry confirmed two drones attacked the US embassy, which said that caused "a limited fire and minor material damage".
Speaking to the NewsNation network, Trump said "you'll find out soon" how the United States would respond, without providing further detail.
The US mission in Riyadh asked its citizens in the capital as well as the cities of Jeddah and Dharan to shelter in place, while the US State Department ordered its "non-emergency" staff and their families to leave Bahrain, Jordan and Iraq.
Qatar, which had comparatively good relations with Iran before the war, said it shot down two Iranian bombers, the first time a Gulf Arab country has hit planes from their giant neighbour.
The Israeli military for the second day carried out strikes on Lebanon, with its military saying it was targeting Iran-backed Hezbollah after the militant group claimed rocket and drone attacks on Israel.
As the conflict spread, Israel's Prime Minister Benjamin Netanyahu said its strikes with the United States on Iran would continue but not become "an endless war".
"It may take some time, but it's not going to take years," he told Fox News in an interview broadcast Monday.