BANGKOK, Thailand — Only four weeks after parts of Thailand’s Andaman coast were battered by devastating tsunamis, a boat has capsized, dealing another blow to the country’s tourist industry.

News agencies on Tuesday reported that seven people were killed in the boating accident, including four Western tourists, after the vessel they were traveling in capsized between the holiday islands of Koh Samui and Pha-Ngan in the Gulf of Thailand.

Almost 20 people remain missing in the accident, which authorities believe was caused by an overloading of the speed boat.

Reuters reports the deceased were all in their 20s, with three of the foreigners being male.

As yet, there is no information on the nationalities of the victims.

The boat, which was carrying about 40 people, was ferrying tourists back to Koh Samui after a full moon party on Pha-Ngan, an island popular with young backpackers for its dance festivals and cheap lodgings.

The Associated Press reported the accident as occurring about five kilometers (three miles) from Koh Samui, at about 5 a.m. (2200 GMT).

AP said nine people had been admitted for treatment in a hospital on Koh Samui.

Many tourists have chosen the Gulf as an alternative Thai holiday destination after the devastating December 26 tsunamis hit the Andaman side of Thailand’s north-south running peninsula.