Two mortar shells exploded inside Israel near the Israel-Syria border in the Golan Heights Saturday, causing no injuries or damage, according to initial reports.

The explosions were believed to be strays from fighting between rebel groups and government troops on the Syrian side of the Golan.

On Thursday, the IDF said it was raising the level of alert following the intense fighting across the border amid reports that the Quneitra crossing was seized by the Nusra Front, a rebel group affiliated with al-Qaeda, and in light of the abduction of 44 Fijian UN peacekeepers and the siege of 110 Filipino UN troops by the group.

On Saturday, 75 UNDOF peacekeepers in the Golan Heights fled Syrian territory for the Israeli-controlled Golan after their positions were attacked by rebel forces, and dozens of peacekeepers from the Filipino contingent were freed under fire from the rebel groups who had surrounded their position.

Speaking on condition of anonymity, UN soldiers said part of the encircled Filipino contingent had been brought out and that others were no longer in rebel hands but awaiting better security conditions so they could enter the Israeli-controlled part of the plateau.

An Israeli military spokesman confirmed that a number of UN peacekeepers entered Israel. He spoke on condition of anonymity. Channel 2 said 75 UN troops had crossed the borders, after two UN positions on the Syrian side of the border were targeted by al-Nusra rebel forces.

Clashes continued in the area through Saturday.

Philippine Defense Secretary Voltaire Gazmin told reporters Saturday in a series of text messages that Filipino troops manning one UN encampment had been “extricated,” while soldiers in another encampment were “now under attack.”

Asked if there was a fresh firefight Saturday, Gazmin replied: “Yes.”

Military spokesman Lieutenant Colonel Ramon Zagala later told AFP that “there is still an ongoing standoff but there was a firefight earlier today.”

“All our troops are safe,” he said.

Activists and officials confirmed to AP that clashes had erupted between the al-Qaida-linked Syrian rebels and UN peacekeepers, after the militants surrounded their encampment.

The IDF announcement on upping readiness also came following the capture and execution of 160 Syrian soldiers by the Islamic State, gruesome pictures of which appeared online Thursday.

Illustrative photo of Israeli soldiers training in the Golan (photo credit: Abir Sultan/Flash90)

Illustrative photo of Israeli soldiers training in the Golan (photo credit: Abir Sultan/Flash90)

On Wednesday, the Quneitra crossing was seized by rebel combatants, including members of the Nusra Front, one of the main groups fighting forces loyal to Syrian President Bashar Assad for control of the embattled country.

“Al-Nusra Front and other rebel groups took the Quneitra crossing, and heavy fighting with the Syrian army is continuing in the surrounding area,” said Rami Abdel Rahman, director of the Syrian Observatory for Human Rights, a Britain-based NGO.

Also Wednesday, at least seven mortars fired from Syria landed in the Israeli side of the Golan Heights. The IDF said it had not determined whether the mortars were fired into Israel intentionally, or were a spillover from fighting between rival factions on the Syrian side of the border.

One Israeli man was lightly wounded Wednesday after a mortar landed near him, and earlier, an IDF officer was moderately injured as a result of stray fire from fighting between rebel groups and forces loyal to Syrian President Bashar Assad in Syria.

The Israel-Syria border region has seen intermittent exchanges of fire throughout the war in Syria. Although Israel has largely attributed these incidents to stray fire from clashes in Syria, there have been attempts to target Israeli soldiers.

In one deadly incident in June, a 15-year-old was killed when the car he was riding in was targeted by an anti-tank missile fired from the Syrian side, just south of the Quneitra crossing.

In June, the UN Security Council strongly condemned the intense fighting between Syrian government and opposition fighters in the Golan Heights and demanded an end to all military activity in the area. Syrian mortars overshooting their target have repeatedly hit the Israeli-controlled Golan, and UN peacekeepers have been abducted.

Thursday’s UN statement noted that UNDOF peacekeepers who were detained by armed forces in March and May were later safely released.

As of July, UNDOF has 1,223 troops from six countries: Fiji, India, Ireland, Nepal, the Netherlands and the Philippines.

But the Philippine government last week said it would bring home its 331 peacekeeping forces from the Golan Heights after their tour of duty ends in October, amid the deteriorating security in the region.

In June 2013, Austria said it was withdrawing its 377 UN peacekeepers from the Golan Heights. Croatia also withdrew in 2013 amid fears its troops would be targeted.