Several people remained missing Monday after a tourist boat carrying more than 40 tourists, many of them American, sank off the Mexican coast, Fox News reported early Monday.

The television network said the ship left the port of San Felipe on the Sea of Cortez on Saturday and capsized during an electrical storm Sunday.

Citing El Mexicano newspaper, the network said that all but nine of 42 passengers on board had been rescued by the Mexican navy.

However, other unconfirmed reports put the number of missing at 23.

The accident occurred off Punta Bufeo, near Puertecitos, 87 miles (140 kilometers) south of the northern city of San Felipe, on the Baja California peninsula, Fox News said.

The incident was under investigation.