Donald Trump accused some Western allies of ingratitude after several countries refused his request to deploy warships to escort oil tankers through the Strait of Hormuz.
The critical Strait of Hormuz, through which 20% of the world's oil and liquefied natural gas flow, remains largely closed off, raising energy prices and fears of inflation.
Several U.S. partners, including Germany, Spain and Italy, said they had no immediate plans to send ships to help reopen the strategic waterway, which Iran has effectively shut with drones and naval mines.
"We lack the mandate from the United Nations, the European Union or NATO required under the Basic Law," German Chancellor Friedrich Merz said in Berlin, adding that Washington and Israel had not consulted Germany before launching the war.
Trump, speaking at a White House event in Washington late Monday, said many countries had told him they were prepared to help, but voiced frustration with some long-standing allies.
"Some are very enthusiastic about it, and some aren't," he said, without offering specifics. "Some are countries that we've helped for many, many years. We've protected them from horrible outside sources and they weren't that enthusiastic. And the level of enthusiasm matters to me."
Trump said earlier Monday that Iran’s retaliatory strikes against its neighbors, including Qatar, Saudi Arabia, the United Arab Emirates, Bahrain and Kuwait, were a surprise.
"They (Iran) weren’t supposed to go after all these other countries in the Middle East," he said. "Nobody expected that. We were shocked."
However, Trump was warned that attacking Iran could trigger retaliation against U.S. Gulf allies, according to a U.S. official and two sources familiar with U.S. intelligence reports.
Oil prices rose more than 2% in early trade Tuesday, reversing some of the previous session's losses, on worries about supply, while Asian shares also rallied after Monday's sell-off.
The war has killed at least 2,000 people across the Middle East since the U.S. and Israel attacked Iran on Feb. 28, including at least 200 children in Iran, according to Iranian Foreign Minister Abbas Araqchi.
At a burial site in Iran on Monday, Marzia Rezaei wept for her son Erfan Shamei, who died in a blast at a military training camp days before he was due home on leave.
"Just an hour before he was martyred, he spoke with me and then I never saw him again. He was supposed to come today," she said.
