PROSPERIDAD, Philippines - Tribal gunmen refused to hand over 47 hostages on Sunday as a 4-day kidnap drama in Sitio Maitom, Agusan del Sur took a bizarre twist with demands for animal sacrifices.

"The negotiations are in stand-off," said Alfredo Plaza, a government spokesman for the negotiating team.

About 400 soldiers and police were on standby around the gunmen's mountain hideout on the strife-torn southern island of Mindanao.

In an effort to placate the kidnappers, negotiators said they would bring tribal leaders to sacrifice animals as part of a ritual demanded by the gunmen's leader, Ondo Perez, in overnight talks.

Provincial Vice Governor Santiago Cane said he would bring tribal leaders to meet with Perez near his hideout.

Asked if this would lead to the release of at least some hostages, one tribal leader named Josue Duhac said "hopefully."

"We will ask assistance from our god to help us and solve this problem because this is a custom and tradition of our people. We are going to use chickens and pigs. All of these will be sacrificed," Duhac told reporters.

Perez had earlier said he would free the remaining hostages on Sunday morning but this did not happen. Vice Governor Cane would not say when the hostages might be released.

"We still are not sure about everything. We are still trying to find a way," he said.

The kidnapping was part of a wave of violence that has swept the southern Philippines, where Muslim and communist insurgents mix with warring clans, pirates and corrupt officials.

President Gloria Macapagal-Arroyo lifted martial law over Maguindanao province on Saturday after 8 days of emergency rule triggered by the massacre last month of 57 people in Mindanao.

The massacre was allegedly by the heads of a Muslim clan that had ruled the area since 2001.

Islamist militants on the southern island of Basilan are holding 3 hostages after beheading another captive on Wednesday.

The gunmen led by Perez, former communist guerrillas and members of the mountain-dwelling Manobo tribe, raided a school in a small farming village in the Agusan valley region of Mindanao on Thursday, taking 75 hostages.

The kidnapping centred on a tribal conflict between rival leaders in the unstable region.

Twenty-eight hostages, including 18 children, were later freed and Perez had said the rest would follow on Sunday. But negotiators said one major hitch was Perez's demand for the arrest of members of the rival faction.

One rival tribesman, Joel Tubay, who has an outstanding arrest warrant for murder, remained in hiding and had refused to turn himself in.

"We are awaiting words from Joel Tubay in regards to his coming out. We are still waiting," said Plaza, the negotiators' spokesman.

Perez had also demanded the dropping of murder charges against him, and that bodyguards to a rival Manobo family be disarmed. It was not clear if those demands would also be met. -With Jeff Canoy, ABS-CBN News