Foreign ministers from 16 Asian nations called on Tuesday for the unconditional release of Korean hostages being held by the Taliban in Afghanistan and observed a minute's silence in memory of two already executed.

"The foreign ministers expressed their deepest sympathy to the bereaved families, people and government of South Korea," said a statement issued by the 10-member Association of South East Asian Nations (ASEAN), Japan, South Korea, China, India, Australia and New Zealand after a meeting in Manila.

"They issued an appeal for the immediate and unconditional release of the remaining hostages to enable them to reunite with their loved ones."

The 18 women and five men, all from South Korea, were kidnapped nearly two weeks ago south of Kabul. Two of them have been killed.

Alberto Romulo, the Philippines' foreign affairs secretary, said the statement was an expression of solidarity with South Korea, one of ASEAN's closest partners.

"There can be no justification for the taking of innocent life or the taking of hostages, even in countries where there is conflict or which is recovering from conflict," Romulo said, adding the release of hostages must be "swift and safe".