Philippine troops and police searched Monday for a 78-year-old Irish missionary after heavily armed men abducted him from the garden of his residence in the country's volatile south.

Six gunmen dragged Rev. Michael Sinnott into a van in front of his horrified aides inside the Columban House compound in Zamboanga del Sur province late Sunday, regional police commander Angelo Sunglao said.

"They could not do anything because the abductors had powerful weapons," Sunglao said.

The abductors took Sinnott away by sea on a motorboat toward the town of Tukuran, Sunglao said, citing fishermen who saw the incident. The van was later found abandoned and burned near the Catholic mission house.

Sinnott's group, the Missionary Society of St. Columban, said he was taking an evening stroll in the convent's garden when he was abducted. The group appealed for prayers for his safe recovery.

The Columban regional director, Patrick O'Donoghue, said he was worried because Sinnott has a heart condition and was not carrying his medication when he was taken.

No group has claimed responsibility for the kidnapping but suspicion fell on Muslim guerrillas who have been fighting for a separate homeland in the predominantly Roman Catholic nation for decades and have in the past kidnapped foreigners, including priests.

In June 2007, an Italian priest, Giancarlo Bossi, was kidnapped allegedly by members of the Moro Islamic Liberation Front or the more violent Abu Sayyaf group. He was freed after 39 days.

The rebel front denied any involvement and the government denied speculation that a ransom was paid to win Bossi's release.

With files from The Associated Press