US President Donald Trump called on Iran on Saturday to "immediately stop" its support for "Houthi terrorists" in Yemen, after the US president announced "decisive" strikes against them.

Trump wrote on his social media platform, Truth Social, that "support for Houthi terrorists must stop immediately. Do not threaten the American people, our President, or the world's maritime shipping lanes. If you do, beware, because America will hold you fully responsible, and we will not give you gifts."

Trump said on Saturday that he had ordered the military to launch strikes against the Houthi group in Yemen in response to the group's attacks on ships in the Red Sea, warning them of the consequences if they did not cease their attacks. He added, "If you do not, you will witness hell like you have never seen before."

The Yemeni capital, Sanaa, was subjected to airstrikes, according to Houthi-affiliated television, following the US president's statement. Al-Masirah TV reported that "an American-British aggression targeted a residential neighborhood in the Shu'ub district, north of the capital, Sanaa, with airstrikes."

A spokesman for Yemen's Houthi-run health ministry said at least nine civilians were killed and nine others wounded in the strikes on Sanaa.