HODEIDA, Yemen — The boat packed with dozens of Somali refugees was more than 30 miles off war-torn Yemen’s coast when a military vessel and a helicopter gunship swooped in, opening fire in the dead of night Friday, killing at least 42 people. Yemen’s Shi’ite rebels blamed the attack on a Saudi-led coalition, highlighted the perils of a heavily used migration route running from the Horn of Africa to the oil-rich Gulf, right through Yemen’s civil war.

The coalition has been heavily bombarding the nearby coast around the Yemeni port of Hodeida, where it accuses the rebels, known as Houthis, of smuggling weapons in small boats. There was no immediate coalition comment.

A Yemeni trafficker who survived the attack said the boat was filled with Somali refugees, including women and children, who were trying to reach Sudan from Yemen, which has been racked by conflict for more than two years.

Al-Hassan Ghaleb Mohammed said in an interview that the boat left from Ras Arra, along the southern coastline in Yemen’s Hodeida province, and was 30 miles off the coast, near the Bab al-Mandab strait, when the military vessel opened fire, followed by the helicopter gunship.

He described a scene of panic in which the terrified refugees waved flashlights, apparently to show they were not combatants. He said the helicopter then stopped firing, but only after dozens had been killed. Mohammed was unharmed in the attack.

Video of the aftermath showed dozens of slain migrants, along with others who suffered gunshot wounds, lost limbs, or had broken arms and legs.

The UN refugee agency said on its Twitter account that it was ‘‘appalled by this tragic incident, the latest in which civilians continue to disproportionately bear the brunt of conflict in Yemen.’’

Associated Press