Kidnappers have released three aid workers abducted in Tipo-Tipo town in Basilan province on Monday morning, a military spokesman said Tuesday.

Lt. Col. Edgard Arevalo, spokesman of the Armed Forces' Philippine Navy, said aid workers Ludivina Dekit, Romy de los Reyes , and Jun Estandarte have been released by their kidnappers late Monday "without paying ransom."

Arevalo said the three were released in Al-Barka town through the efforts of Tipo-Tipo Mayor Tong Istarul.

The Navy spokesman said two more aid workers identified as Esperanza Hupida and Millet Mendoza remained in the hands of the kidnappers.

Earlier reports said there were three women and a man in the group, but they Philippine Navy said five from a group of 12 people in an aid convoy were abducted after their vehicles were stopped by armed men in Barangay Cabangalan in Tipo-Tipo.

The aid workers were on their way to Isabela City, reports said.

The five, who worked for a group funded by a Malaysian charity, were abducted in an area known as a hotbed of the Abu Sayyaf, which the military says has ties to Osama bin Laden's Al-Qaeda network.

Arevalo said the military and the police continued rescue operations for the two remaining captives, while the local government of Tipo-Tipo was negotiating with the kidnappers. With Agence France Presse