Islamic militants holding a television presenter hostage in the southern Philippines agreed to extend the deadline for a ransom by two hours, a negotiator said on Tuesday.

The kidnappers had threatened to behead ABS-CBN network host Cecilia "Ces" Drilon, 46, and her two colleagues at noon (0400 GMT) if the money was not delivered but the negotiator said he convinced them to extend the deadline to 2:00 pm (0600 GMT).

It was not clear what would happen after this deadline passes but Jun Alvarez, an emissary in the talks, said: "the kidnappers indicated they would not do anything until two o'clock.

"After that, they will say something to us," he added.

ABS-CBN television journalist Ces Drilon, her cameramen Jimmy Encarnacion and Angelo Valderama, and university professor Octavio Dinampo, were heading to a secret meeting in Jolo island with a senior Abu Sayyaf leader when they were seized on June 8.

The abductors freed Valderama on June 12 after a ransom of 100,000 pesos (about 2,250 dollars) was paid.

"They told us on Monday that if an agreement was not reached by noon Tuesday then by two o'clock, they will cut off the heads of all of them," Alvarez said.

The negotiators have tried to placate the kidnappers by offering them development projects in their communities rather than ransom which was difficult to deliver, Alvarez said.

The Abu Sayyaf gunmen are believed to have demanded a ransom thought to be about 1.12 million dollars from Drilon's family.

President Gloria Arroyo has ordered police and troops to recover the hostages alive, as military reinforcements arrived in the area on Sunday.

The small group of militants, founded with money provided by Al-Qaeda chief Osama bin Laden in the early 1990s, have been blamed for the country's worst terrorist attacks as well as for kidnappings of western tourists and Christian missionaries.

In the past, the Abu Sayyaf has beheaded their captives when ransom was not delivered in time.

Alvarez said he spoke to Drilon earlier on Tuesday and that she was "okay" and was asking people to pray for her.