Ms Asmizar holding up a mobile phone on March 31 in Padang, West Sumatra province in Indonesia, showing a photograph of her son Wendy Rahadian - one of 10 members of a tugboat crew kidnapped by Islamic militants in the Philippines.

The Indonesian sailors were kidnapped in the waters of the conflict-racked southern Philippines by Abu Sayyaf terrorists, said Kompas news website.

The militants have demanded a ransom for the Indonesians' release, authorities said on March 29.