Yemen’s Houthis said a strike they blamed on the United States killed a guard at a communications tower on Thursday, as the Houthi media reported more than 20 strikes before dawn.

There was no immediate statement from Washington, which has carried out a wave of strikes against Houthi targets in recent weeks after President Donald Trump vowed to pummel the group until they stop attacking commercial shipping in solidarity with Palestinian militant group Hamas.

“An American aggression targeted the communications network in... Ibb governorate, leading to the martyrdom of Abdulwasim Abdulwahab Zahir, the communications tower guard,” Houthi health ministry spokesman Anees Alasbahi said on social media.

The Houthis’ Al-Masirah television said more than 20 strikes had hit Saada province, the militant group’s stronghold in the northern mountains.

It said Washington had carried out two strikes on vehicles, one south of the Houthi-held capital Sanaa and another in Saada province.

On Wednesday, the group said five people were killed in two waves of strikes on Hodeida province on the Red Sea coast.

Houthi-held areas of Yemen have seen near-daily strikes blamed on the United States since Washington launched an air campaign against the Houthis on March 15.

Washington has since said it is sending a second aircraft carrier group to Middle East waters to bolster its campaign to “deter aggression and protect the free flow of commerce”.

The Houthis had halted their attacks on shipping during a six-week ceasefire in Gaza earlier this year, but they announced they were resuming them after Israel cut off aid to the Palestinian territory before returning to fighting.

Since then, the Houthis have launched drone and missile attacks on both US warships and Israel.

The group form part of the so-called Axis of Resistance, an Iran-backed alliance of Middle East groups opposed to Israel and the United States.

Their campaign of attacks on merchant vessels over the past two years has prompted many shipping firms to avoid the route through the Red Sea and Suez Canal that normally carries about 12 percent of world maritime traffic.

The costs of the resulting detour around the tip of southern Africa have been a factor in pushing up world prices.