At least five people have been killed in an attempted jailbreak in the Philippines led by members of Muslim militants Abu Sayyaf, police say.
Police say some 129 Abu Sayyaf suspects are in the jail
Talks to end Monday's stand-off in Manila, which began when a group of about 10 inmates snatched weapons from their guards, have stalled.
At least three guards and two prisoners were shot in the fracas, police said.
The inmates at the Camp Bagong Diwa maximum security jail in Manila had earlier agreed to surrender.
"They changed their minds," said Avelino Razon, police chief for the metropolitan Manila area.
Negotiations apparently ground to a halt after the gunmen demanded that food be sent inside the prison.
"If they will surrender, lay down their arms and come out, they will get food," Mr Razon said, according to the Associated Press.
"We are exhausting all possible means to resolve this peacefully," he said, adding, "the military option, which is the final option, is still there."
Mujib Hataman, a Muslim congressman who was negotiating with the inmates by telephone, said they had demanded timely trials, assurances they would not be harmed, the right to air their grievances to authorities, and interviews with the media.
Police have surrounded the four-storey building in the Taguig district.
Earlier, the prisoners contacted a local radio station, demanding talks with two senior Muslim officials and film star Robin Padilla, a Muslim convert.
Police said they believed the prisoners were led by Alhamser Limbong and Kair Abdul Gapar.
Limbong, also known as Commander Kosovo, has been allegedly involved in a mass kidnapping in 2001-02 that left several hostages dead, including two Americans.
He has also been charged with carrying out a bomb attack on a ferry near Manila that killed more than 100 people in 2004.
Gapar has also been charged with a string of kidnappings.
Police said there were about 129 suspected members of Abu Sayyaf out of more than 400 inmates in the jail.
Abu Sayyaf - which mainly engages in kidnap for ransom - is one of four Muslim rebel groups operating mostly in the southern Philippines.
It has been labelled a terrorist organisation by both Manila and Washington, and is believed by the US to have links with Osama Bin Laden's al-Qaeda network.
The Philippine government has deployed thousands of troops in the south in an effort to eradicate the Abu Sayyaf.