US President Joe Biden
US President Joe BidenREUTERS/Jonathan Ernst/Pool

US President Joe Biden said on Saturday that the United States had delivered a private message to Iran about Iran-backed 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, according to Reuters.

His comment followed US and British strikes against Houthi targets overnight Thursday and again on Friday.

The Houthi movement has threatened a "strong and effective response" after the second strike, which the US said hit a radar site.

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.

The US and British strikes followed a sharp rise in attacks by the Iranian-backed Houthis since the start of the war in Gaza on October 7.

On Tuesday, the US and British armies shot down 21 drones and missiles fired by the Houthis towards the Red Sea, in what was one of the biggest attacks by the group to date.

Yahya Sare'e, the military spokesman for the Houthis, claimed last week that the group attacked a ship that refused the Houthis' orders to stop and was on its way to Israel.

22 nations recently agreed to participate in a US-led coalition to safeguard commercial traffic in the Red Sea from Houthi attacks.