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 the eastern and northern outskirts of Gaza City overnight Saturday to Sunday, destroying buildings and homes, residents said, as Israeli leaders vowed to press on with a planned offensive on the city.
The Pentagon is working on plans to deploy the US military to Chicago as President Donald Trump says he is cracking down on crime, homelessness and undocumented immigration, the Washington Post reported on Saturday.
Thousands of Australians joined pro-Palestinian rallies on Sunday, organisers said, amid strained relations between Israel and Australia following the centre-left government's decision to recognise a Palestinian state.
North Korean leader Kim Jong Un supervised the firing of new air defence missiles to test their combat capability, state media KCNA reported on Sunday.
Portugal's authorities have said that between July 27 and August 15, 1,331 excess deaths from extreme heat were reported, with the over 75 age group particularly hard hit, Euronews reported on Saturday.