Former Malaysian senator Sairin Karno expressed anger at Presidential Spokesperson Rigoberto Tiglao for having revealed Philippine Senator Panfilo Lacson's plan to negotiate for alleged ransom payment to the Abu Sayyaf.

"I will not balk at the threat of the Malaysian national to file a libel suit against me," said Tiglao, adding, "It was not me, but Senator Lacson who first revealed his intervention and efforts to negotiate with the Abu Sayyaf to release American missionaries Martin and Gracia Burnham."

"The Malaysian senator should instead call Senator Lacson a liar," said Tiglao.

"Negotiations for the release of the hostages are not between the Philippines government and the Abu Sayyaf. It is (now) between the Abu Sayyaf and Malaysia," said Tiglao, who interpreted the presence of two Malaysian nationals who have been contacting Philippine government negotiators for the release of hostages last year and this year.

Lacson earlier revealed that his friend Karno had invited him to join the negotiations. He admitted he secretly went to Sabah recently "to work out the release of the hostages without having to pay ransom". In another instance, Lacson claimed that ransom payment always accompanied the release of hostages.

Karno has been talking regularly with Abu Sayyaf members and current Philippine government negotiators. "He has been insisting he could work out with the criminals the release of the hostages," revealed Tiglao.

"Our intelligence services have reported that another Malaysian, Yusuf Hamdan, has been using Karno's name or has been representing him, with his permission," said Tiglao.

"Karno and Hamdan are known to be associates," said Tiglao. They worked together with Zamboanga-based Lee Peng We, former president Joseph Estrada's adviser on Mindanao affairs, for the release of 40 hostages abducted in Sipadan, Sabah and in Jolo, Sulu from April to August last year.

Sources said the Abu Sayyaf received more than $20 million in ransom from non-government organisations in Libya, Malaysia and Europe last year. Other sources allege former government negotiator Roberto Aventajado asked for 40 per cent of the ransom payment at that time.

The ransom enabled the Abu Sayyaf to buy high-powered firearms, speedboats and ammunition, which they used effectively to abduct 20 tourists, including three American nationals, from a south-western Philippines resort in May.