Kidnappers holding a Chinese tourist who was abducted from a resort on Malaysia's Borneo island have made a phone call to her family in China, a senior security official said Sunday.

He said the gunmen have communicated with the family of Gao Huayuan, 29, whom Philippine security forces believe is being held in Jolo island in the southern Philippines.

"They have made telephone contact with her family," Mohammad Mentek, director-general of the security command in the east of Malaysia's Sabah state, told AFP.

The Abu Sayyaf, a small band of militants infamous for kidnapping for ransom, are the prime suspects in Wednesday's abduction of the Chinese tourist and a Filipina resort worker, Marcy Dayawan, 40.

Mohammad said Malaysian authorities believe the two hostages are safe.

"We hope they will be returned safely to their families as soon as possible," he said.

Mohammad declined to comment on whether the kidnappers had began ransom negotiations with the Chinese family.

Philippine authorities believe the kidnappers are affiliated with Abu Sayyaf "sub-commander" Murphy Ambang Ladjia, who was involved in a spectacular kidnapping of 21 people from another resort in Sabah -- in the north of Borneo island -- in 2000.

Twenty of those hostages -- many of whom were Europeans or other foreign tourists -- were released within five months, reportedly after hefty ransoms were paid.

A final Filipino captive was held until 2003.

Mohammad said security forces had strengthened their presence, with more sea patrols along the coastal waters of Sabah which are a major diving attraction for foreigners.

"But we are not able to be everywhere all the time since our sea borders with the Philippines are wide and porous," he said.

- Philippines scours islands -

The Philippine military said Sunday troops were intensively searching remote southern islands and surrounding waters for the two female hostages, although there have been no sightings of them or other confirmation of their whereabouts.

The search focused on the Basilan, Tawi-Tawi and Sulu islands in the country's far south which are known hotbeds of the Abu Sayyaf, said regional military chief Lieutenant General Rustico Guerrero.

He said a "naval task force" had been "conducting extensive search and naval blockades (of) suspected sea crafts" while ground troops had also been deployed.

The military said Abu Sayyaf gunmen aboard a speedboat were believed to have taken the women to Simunul, part of the Tawi-Tawi islands and a day's boat ride across the border.

But Guerrero said the search also covered the nearby Sulu archipelago as well as Basilan, in whose jungles the Abu Sayyaf had taken hostages in the past.

"It takes a lot of resources and effort to cover (the sea areas)," he said. "The sea area is so huge and we have limitations."

Asked whether there was any definitive indication that the gunmen and their hostages had reached land, he said: "We have no confirmation."

Philippines' armed forces spokesman Lieutenant Colonel Ramon Zagala said Sunday there were "positive leads" in the search, although he was not at liberty to disclose them.

The Abu Sayyaf have only a few hundred gunmen but have been blamed for the worst terror attacks in Philippine history, including bombings and kidnappings that have often targeted foreigners or Christians.

The group was set up in the 1990s, reportedly with seed money from Al-Qaeda mastermind Osama bin Laden.

Last November suspected Abu Sayyaf gunmen kidnapped a Taiwanese couple holidaying in another Sabah resort.

The husband was killed during the abduction.

His wife was freed -- after a ransom was believed to have been paid -- after being held for 36 days on the main Sulu island of Jolo.

The Abu Sayyaf are believed still to be holding other foreign hostages, including two European bird-watchers abducted in Tawi-Tawi in February 2012.