A sailor was seriously injured in the attack launched by Yemen’s Houthi rebels on Thursday against a Ukrainian ship in the Gulf of Aden, the US Central Command (CENTCOM) announced.

The Ukrainian-owned Palau-flagged M/V Verbena was hit by two missiles that caused a fire on board, according to a CENTCOM statement.

Yemen’s Houthi rebels have claimed responsibility for three attacks on merchant ships in the past 24 hours. In addition to the missile attack on the Verbena in the Gulf of Aden, the Houthis also targeted the SeaGuardian and Athina ships in the Red Sea, their spokesman Yahya Sharia said during the televised briefing.

Since last November, Iran-aligned Yemeni rebels have frequently launched missile and drone attacks against merchant ships in the Red Sea, Gulf of Aden and the Indian Ocean. They initially said they were targeting ships linked to Israel, but later expanded their targets to include ships linked to the US and Britain, in retaliation for strikes against their positions in Yemen by forces from those countries.

Houthi attacks in the region have caused problems for global shipping, forcing companies to send their ships on time-consuming and more expensive voyages around southern Africa.