The government had tried its best to free Abu Sayyaf group hostage Bernard Then Ted Fen before he was reported killed, said Deputy Prime Minister Datuk Seri Ahmad Zahid Hamidi.

Ahmad Zahid, who is also Home Minister, said the group had earlier promised the Malaysian negotiators to free Then, 39, and another victim, Thien Nyuk Fun, 50.

"Unfortunately, they have fixed several additional conditions and this was unacceptable to the negotiators," he said after a signing ceremony of an agreement on Preventing and Tackling Serious Crimes with the United States, here today.

Then and Thien were kidnapped by a group of gunmen who rushed into the Ocean King Restaurant in Sandakan at 7.45pm on May 14.

Thien, who is the restaurant manager, was freed by the group from southern Philippines via a negotiation between the Malaysian government and the group on Nov 8.

Commenting further, Ahmad Zahid said the Philippine authorities has not officially confirmed that the decapitated head found in Jolo, Southern Philippines, was Then's.

"We continue to work with the Philippines, not only with the Filipino authorities, and the negotiation team continues to carry out their duties and the information received had been channelled to Bukit Aman and the Home Minister for further action," he said.

He said Malaysia respected the Philippine's sovereignty and requested the full cooperation of the Philippine government in taking further action in accordance with international practise including conducting DNA test.

Ahmad Zahid also stressed that the government would endeavour to bring back the victim's body after confirmation is made.

In another development, he said Malaysia was prepared to face any possibility of an attack by certain quarters as had transpired in Paris, France.

"With what had transpired in Paris, it is perceived that certain parties are motivated to carry out the same attack, but we are very confident of the capability and ability of the Royal Malaysian Police in ensuring that they (terrorists) will not make any such effort," he said.

He said Malaysia had boosted its preparedness at the sea, land and air entry points via the cooperation of the Malaysian Maritime Enforcement Agency, marine police and several other enforcement agencies.

On Nov 13, an estimated 100 people were killed in bombing and firearm attacks at the Bataclan concert hall, restaurants in the town centre and near Stade de France in Paris.