US President Joe Biden has said that attacks on the Houthis will continue even as he acknowledged that the group have not stopped their Red Sea attacks.
The US carried out a fifth round of strikes on Yemen on Thursday after a US ship was struck by a Houthi drone.
White House spokesman John Kirby told reporters that US forces "took out a range of Houthi missiles" that were about to be fired towards the Red Sea.
He said the American attacks took place on Wednesday and again on Thursday.
On Wednesday, a Houthi drone hit a "US owned and operated bulk carrier ship". It came as the US designated the Houthis as a terrorist organisation.
"Well, when you say working are they stopping the Houthis? No," Mr Biden told reporters in Washington DC on Thursday before he left for a speech in North Carolina.
"Are they gonna continue? Yes."
The Houthis began attacking merchant vessels in November, saying they were responding to Israel's military operation in Gaza. Since then, the group has launched dozens of attacks on commercial tankers passing through the Red Sea, one of the world's busiest shipping lanes.
In response, the US and UK launched a wave of air strikes against dozens of Houthi targets on 11 January. The strikes - supported by Australia, Bahrain, the Netherlands and Canada - began after Houthi forces ignored an ultimatum to cease attacks in the region.