President Joe Biden said on Saturday the United States had delivered a private message to Iran about Houthis responsible for attacking commercial shipping in the Red Sea.
"We delivered it privately and we're confident we're well-prepared," Biden told reporters at the White House before departing to the Camp David presidential retreat for the weekend.
The Houthi movement threatened a "strong and effective response" after the United States carried out another strike in Yemen on Friday night, further ratcheting up tensions as Washington vows to protect shipping from attacks by the Iran-aligned group.
The latest strike, which the US said hit a radar site, came a day after dozens of American and British strikes on Houthi facilities in Yemen.
White House spokesperson John Kirby said on Friday the initial strikes had hit the Houthis' ability to store, launch and guide missiles or drones, which the group has used to threaten shipping.
He said Washington had no interest in a war with Yemen.
Biden, whose administration removed the Houthis from a State Department list of "foreign terrorist organisations" in 2021, was asked by reporters on Friday whether he felt the term "terrorist" described the movement now. "I think they are," Biden said.
Israeli planes and tanks pounded areas across the Gaza Strip overnight and on Sunday, destroying several residential buildings, witnesses said, as Palestinians desperately awaited implementation of a US plan to end the war.
The number of students confirmed dead after the collapse of a boarding school building in Indonesia rose to 36, from 16 a day earlier, the country's disaster mitigation agency said on Sunday.
President Donald Trump told Israel on Friday to immediately stop bombing Gaza after Hamas agreed to release hostages and accept some other terms in a US plan to end the war, but issues like disarmament appeared unresolved.
Japan's ruling party picked hardline conservative Sanae Takaichi as its head on Saturday, putting her on course to become the country's first female prime minister in a move set to jolt investors and neighbours.