Eight naval ships from the Philippines and Malaysia began Sunday an annual joint border patrol training exercises, the navy said.

Five Malaysian and three Philippine naval ships sailed off from the southern port city of Zamboanga for the week-long exercises, Filipino navy commander Nelson Panes said.

"The joint exercise would last about a week and will close in Sabah, Malaysia," Panes said.

Three of the Malaysian vessels were warships while the others were from Malaysia's customs agency, he said.

Enhancing inter-operability

The annual exercises are aimed at enhancing the inter-operability of the naval authorities of both countries, which share a common sea border often used by pirates and terrorists liked the Abu Sayyaf Muslim gang.

Abu Sayyaf guerrillas in 2000 launched two cross-border raids into beach resorts in Sabah and abducted more than a dozen mostly European hostages they later freed allegedly in exchange for hefty ransoms by military count.

The following year, the gunmen kidnapped another batch of hostages from a Philippine beach resort, including three Americans, two of whom were killed later.

Government the Abu Sayyaf's strength has dwindled to a few hundreds, although the group remains a security threat in the south.