Several United Nations peacekeepers from the Philippines who were abducted by Syrian rebels said in videos posted online Thursday that they are safe and sound, even as activists reported clashes and shelling in the area where UN troops are being held.

Opposition fighters detained 21 Filipino peacekeepers near the village of Jamlah in the Golan Heights on Wednesday. The abduction marked the first time since UN troops began patrolling an Israeli-Syrian armistice line in the Golan Heights nearly 40 years ago that UN forces have encountered trouble during their mission, said Timor Goksel, a Beirut-based former United Nations official in the region.

One of the videos posted online shows three men dressed in camouflage and blue bullet-proof vests emblazoned with the UN and "Philippines."

Israeli spy gadgets Syria's state-run news agency says Israeli spying devices have been found in the country's coastal region. SANA's report on Thursday says the devices are designed to photograph, register and transfer data. There were no further details on the objects or the location of the find. Syria and Israel are at a state of war and fought several battles over the past. Israeli warplanes carried out an air raid near Damascus in January. U.S. officials said the target was a convoy of sophisticated Russian SA-17 anti-aircraft missiles. Syria said a research centre was hit.

"We, the UN personnel here, are safe, and the Free Syrian Army are treating us good," one of them says in English. "We cannot go home because the government of [President Bashar al-Assad] do not stop the bombing. To our family, we hope to see you soon and we are OK here."

The second video shows six peacekeepers sitting in a room. An officer, who identifies himself as a captain, says that as their convoy came under shelling on Wednesday, "we stopped and civilian people helped us for our safety and distributed us in different places to keep us safe."

Peacekeepers considered 'guests'

A spokesman for the Martyrs of Yarmouk Brigades, which is holding the peacekeepers, told The Associated Press via Skype that all the 21 peacekeepers "are fine and in good health."

"We consider them guests," he added.

The targeting of the peacekeepers was likely to heighten Israeli jitters about the Syrian civil war upsetting the delicate balance along the frontier between the two countries. Israel captured Syria's Golan Heights in the 1967 Mideast war, and a UN monitoring force, UNDOF, was sent in 1974, a year after another Mideast war, to enforce an armistice deal between Syria and Israel.

The rebel spokesman, who declined to give his name for security reasons, said the peacekeepers' job was to ensure that no heavy weapons, such as tanks, enter the area near the Israeli-Syrian armistice line. For months, the regime has been bringing tanks into the area to fight rebels, he said, adding that helicopter gunships joined the battle late last week.

Asked if the rebels will be ready to hand over the peacekeepers to an international organization, he said "the command will have to decide about that." He added that once these peacekeepers leave the area the regime could kill "as many as 1,000 people."

He said at least 10 people have been killed and dozens wounded in the shelling of Jamlah and nearby villages.

On Thursday, Syrian troops battled rebel fighters near the Golan Heights, in the southern Syrian province of Daraa, according to Rami Abdul-Rahman, the director of the Britain-based Syrian Observatory for Human Rights activist group. He said the fighting was concentrated on the outskirts of Jamlah, about one kilometre from Israeli-controlled territory.

In an amateur video posted online Wednesday, a man identified as a spokesman for the Martyrs of Yarmouk Brigades said his group will hold the peacekeepers until Assad's forces withdraw from Jamlah.

The Yarmouk Brigades said in a statement on its Facebook page on Thursday that Assad's troops are shelling the village, and warned that the army will be responsible if any harm comes to the peacekeepers in rebel custody.

Release expected within 24 hours

In Manila, the Philippine government said Thursday that the peacekeepers were unharmed and were being treated well. Foreign Affairs Department spokesman Raul Hernandez said the UN force commander in the area is negotiating with the leader of the rebel group.

Philippine President Benigno Aquino III said the commander told him to expect the peacekeepers to be released within 24 hours, with negotiations progressing well.

The UN Security Council has demanded their immediate and unconditional release.

The Observatory said negotiations were under way between the rebels and Arab League and UN officials on handing over the peacekeepers, and that the talks were now focused on what road should be used to deliver the UN troops. It said the rebels want the regime to pull out its vehicles from the area, permanently end the shelling of the area and allow refugees to return.

It was not immediately clear whether UNDOF will keep operating in Syria even if the incident is resolved peacefully. A man who answered the phone at UNDOF's office in Damascus said he was not authorized to give statements referring questions to the UN in New York.

Goksel, the former UN official who now works for Al-Monitor news website, described the members of the peacekeeping force as "a soft target." He said the group is based in Damascus, but that it staffs observation posts along the armistice line, and travels between the Syrian capital and the frontier to deliver supplies and rotate monitors.

"They were never challenged by anybody in Syria until now," Goksel said.

The Yarmouk Brigades, one of scores of groups fighting Assad's troops, was formed a year ago and most of its fighters appear to be young Syrians from poor areas in the south, said Observatory director Abdul-Rahman.

In a statement Thursday, the Western-backed opposition group, the Syrian National Coalition, said its representatives are in contact with rebels in the Jamlah area "to let the peacekeepers go." The statement denied that seizing the peacekeepers amounted to kidnapping, saying the peacekeepers were taken in a "preventive security measure."

Coalition planning interim government

Rebel groups tend to operate independently, despite attempts in December to form a unified military command, and it's not clear whether the local rebels near the Golan will heed calls from exile-based leaders. Rebel fighters tend to see the opposition figures in exile as out of touch.

The Coalition also said Thursday that its leaders would meet in Istanbul next week to elect a prime minister who would head an interim government. The coalition's Turkey-based media office said the interim government would at some point move to rebel-held areas of Syria to operate from there, but that the timetable was not yet set.

The coalition has said in the past that it would set up a Syria-based interim government, but has repeatedly failed to follow through. It was not clear whether the two-day gathering in Istanbul, starting Tuesday, would yield results.