Authorities in the Philippines have begun negotiating for the release of a television news crew who were kidnapped three days ago in the southern island of Jolo. Ces Drilon, an anchorwoman for ABS-CBN, the country's largest television network, a cameraman, driver and a Muslim academic accompanying them were intercepted by armed men on Sunday. Police said they suspect members of the Abu Sayyaf group to be behind the kidnapping. No ransom demand has been made public so far but unconfirmed reports say the kidnappers are asking between $227,000 and $454,000. Joel Goltiao, the regional police chief superintendent, said there was a "great possibility" that the journalists would be freed. "Negotiations are being conducted," he told a local radio. "There is a great possibility that we will obtain the release of Ces Drilon ... but we cannot give an exact date." Goltiao also told journalists to stay away from Jolo because police are unable to ensure their safety. "What happened to Ces may happen to them," he said. Drilon is the third local journalist to be kidnapped by the Abu Sayyaf since 2000. 'Unacceptable' Paris-based Reporters Without Borders said the Abu Sayyaf has been involved in the kidnappings of more than 30 journalists. "We hope that those who have abducted the journalists and their guide will hear the appeals being made on their behalf by many of the country's leading figures," the group said. "Taking hostages is unacceptable. We call on all those could have any influence over the kidnappers to try to get Drilon and her colleagues released." The Abu Sayyaf group is notorious for a string of bombings and kidnappings for ransom and has been linked by Philippine and US intelligence agencies to the al-Qaeda network. The group says it is fighting for a separate Muslim state in the southern Philippines.