Police officers in the Philippines kidnapped and murdered a South Korean businessman before trying to extort money from his wife by pretending he was still alive, according to the country's government.

The man disappeared in October from Angeles, a city in the north of the Philippines, before his wife handed over a ransom worth £116,000, a national police spokesman told AFP. ABC-CBN News in the Philippines named him as Ji Ick-Joo.

Mr Ji, who was in his 50s, had already been strangled and cremated at a crematorium owned by a former police officer, according to South Korea's foreign ministry which cited a Philippines government report. Investigators have summoned workers of the funeral home for questioning.

Yonhap news agency reported that Mr Ji was acquainted with the officers and was active in the labour export sector. They are said to have used a forged arrest warrant to kidnap him under the pretext of a drugs investigation, it said, quoting the foreign ministry.

A ministry spokesman said Foreign Minister Yun Byung Se demanded answers and expressed "grave shock over the implication of Philippine police officers in the case", AFP reported.

National police said one of the accused officers, Ricky Isabel, had surrendered while another two were under investigation. A retired officer is also thought to be involved.

All three accused officers were part of the anti-illegal drugs group based in Manila, the police spokesman added.