Yemen’s Houthi group said late Thursday that US warplanes launched 13 airstrikes targeting the country’s northern provinces of Sanaa, Saada and Al-Jawf. The Houthi-affiliated Al-Masirah TV channel reported that “US aggression aircraft launched an airstrike on Hamdan district in Sanaa province.”

The U.S. is conducting strikes on Yemen from its two aircraft carriers in the region — the USS Harry S. Truman in the Red Sea and the USS Carl Vinson in the Arabian Sea, targeting the Houthis because of the group’s attacks on shipping in the Red Sea, a crucial global trade route, and on Israel.

The death toll from US airstrikes on an oil port in western Yemen has risen to at least 74 people, the Houthi-run health ministry reported, marking the deadliest day since the United States escalated its aerial campaign against the Iran-backed group last month.