MANILA, Feb. 20 (Xinhua) -- A crew man has been killed and seven others abducted after armed men believed to be Islamist militants attacked a Vietnamese boat Sunday night, a spokesman for the Philippine coast guard said on Monday.

Commander Armand Balilo said the incident took place around 7:10 p.m. Sunday in Sulu Sea, 17 nautical miles north of Pearl Bank near Baguan island, Taganak in Tawi-Tawi.

Balilo said the Vietnamese coast guard alerted the Philippines coast guard about the attack in MV Giang Hai, prompting the Philippine coast guard to dispatch two speed boats and some marine soldiers to the area.

He said 17 Vietnamese were rescued by the Philippine team that conducted a maritime patrol in the area. The boat has a total of 25 crew members, he said.

Initial investigation showed that seven crew members were kidnapped by the attackers.

The Vietnamese boat is now anchored in Taganak island, Balilo said.

The Philippines, Malaysia and Indonesia have forged a an agreement to combat piracy and terrorism in their maritime borders.

Many of the kidnapped victims usually end up in the hands of the Islamic extremist group Abu Sayyaf group that operates in the remote southern Philippine islands of Basilan and Sulu off Mindanao.