The Yemeni government has accused Iran-backed Houthis of killing four crew members and two rescue workers in a “double-tap” strike against a commercial vessel sailing through the Bab al-Mandeb Strait in the Red Sea, a serious escalation and a sign that the deadly conflict in Iran is spilling over across the region.

The Ministry of Transport of the internationally recognized Yemeni government said the Houthis fired three ballistic missiles at the Tihamah, a small cargo ship transporting food.

A fire caused by the strikes damaged the ship and killed four crew members – three Pakistani nationals and one Indonesian, the ministry said, adding that four other crew members and a rescue worker were injured.

The ministry accused the Houthis of targeting the vessel once again after the search and rescue operation got under way, in what it said was an effort to “endanger the lives of all onboard, including the rescue teams.”

The Yemeni Coast Guard said later that, according to preliminary information, two rescue workers, as well as the four crew members, were killed during the attack.

There was some confusion over the ownership of the vessel that was struck, with initial reports from Yemeni officials and the marine intelligence group Marisks reporting that an unidentified Saudi-owned ship was struck in the Bab al-Mandeb Strait.

However, according to MarineTraffic, Tihamah is sailing under the Tanzanian flag and is owned by companies registered in Egypt and Yemen.

The Houthis claimed responsibility, saying it was carrying military equipment, the Houthi-run Saba news agency reported Tuesday. Saudi Arabia did not immediately respond to the claim.

Yemen’s Houthi-affiliated Al-Masirah TV released several photographs and a short video purportedly showing the vessel. The name Tihamah was visible in two of the photographs.

The group warned last month they would target any Saudi shipping seeking to transit the strait, in response to a long-standing Saudi blockade against the group, which controls much of northern Yemen.

The Joint Maritime Information Center, which is overseen by the US Navy, said an unidentified general cargo ship was struck by a projectile while stationary in Yemeni territorial waters in the Bab al-Mandeb Strait. Its report on Tuesday did not identify the vessel or say who was responsible for the attack.