Muslim militants released four workers of an electric company who were kidnapped on a southern Philippine island last month, police said Friday. The workers, who were traveling in a jeep when they were stopped and dragged away at gunpoint on the predominantly Muslim island of Basilan, were handed over to government emissaries late Thursday, said Basilan police chief Salik Macapantar. He refused to say if ransom was paid following their 15-day captivity, as has been the case with previous kidnappings by the al-Qaida-linked Abu Sayyaf group. Authorities have warned that kidnappings for ransom and extortion, along with funds from foreign terrorist allies, have allowed the Abu Sayyaf to survive and finance deadly bombings and other atrocities for years. They were believed to be led by a local commander, Nur Hasan Jamiri, who was backed by gunmen linked to the Moro Islamic Liberation Front, the main Muslim rebel group engaged in peace talks with the government, the military said earlier. It was the second Abu Sayyaf kidnapping in a month. Earlier in June, the militants based on nearby Jolo island snatched three journalists, including popular TV news anchor Ces Drilon. They were freed more than a week later, after ransom was paid, police said.