Meanwhile, a Syrian official said President Bashar Assad's troops have the right to enter the Israeli-occupied Golan whenever they wish -- a veiled threat at Israel to stay out of Syria's conflict.
Also Sunday, Damascus rejected Turkey's allegations that Syria was behind two car bombings that killed 46 people in Turkey and wounded dozens more the day before.
The four Filipinos, seized Tuesday, were apparently unharmed, but will undergo a medical checkup and stress debriefing, said Brig. Gen. Domingo Tutaan.
A statement issued by the rebel group holding the peacekeepers -- the Yarmouk Martyrs Brigade -- said the four were handed over to a U.N. delegation in the border area on Sunday, but provided no other details.
The peacekeepers are part of a U.N. contingent that patrols a buffer zone between Syria and the Golan Heights, a plateau Israel captured from Syria in 1967.
It was the second abduction of Filipino peacekeepers since March, when 21 were held for three days by rebels fighting the regime of Assad.
The Philippine foreign secretary has said he would recommend withdrawing Filipinos from the peacekeeping contingent in Syria, but the final decision is up to the country's president.
Nearly 1,000 U.N. peacekeepers are patrolling the Golan Heights. Other major contributors are India and Austria. Croatia has recently withdrawn its contingent.
The buffer zone had been largely quiet for four decades, but tensions have risen there since the outbreak of the revolt in Syria more than two years ago.
In Damascus, Information Minister Omran al-Zoubi told a news conference on Sunday that Syria has the right to enter the Golan Heights.
"The Golan is Syrian Arab territory and will remain so even if the Israeli army is stationed there. We have the right to go in and out of it whenever we want and however we please," he said.
His comments came in response to last week's Israeli airstrikes on Syria which Israeli officials say targeted advanced Iranian missiles intended for Hezbollah.
The strikes marked a sharp escalation of Israel's involvement in the Syrian civil war and raised fears that a conflict that has repeatedly spilled over Syria's borders in the past 26 months could turn into a full-fledged regional war.
Syria has threatened to retaliate but the official response was relatively mute.
"Israel should understand that the Syrian skies are not a picnic for anyone," al-Zoubi warned, adding that Syria would retaliate.
"We are a people who do not forget to retaliate against those who commit aggression against us, and we do not forget our martyrs or those who killed them."
Assad's regime might be reluctant to open a new front against Israel with his army already stretched thin in the deadlocked fight with the rebels.
But he has a history of operating through proxies, such as the Lebanese militant Hezbollah group or radical Syrian-based Palestinian factions who can potentially launch attacks on Israel from the Golan.
The Syrian uprising escalated into a civil war that has claimed tens of thousands of lives and displaced millions of Syrians so far. The two sides have been largely deadlocked on the battlefield.
In the latest violence in the capital, Damascus, six mortar shells struck a neighborhood causing damage and casualties, a Syrian official said on condition of anonymity because he is not authorized to brief reporters.
The mortars hit the predominantly Alawite district of Mazzeh 86 during morning rush hour, he said. Sunday is the first day of the work week in Syria.
Alawites, including Assad, are followers of an offshoot of Shiite Islam, and have dominated government under Assad family rule. Rebels and regime forces have been fighting in parts of Damascus, and have fired mortars at neighborhoods seen as pro-Assad.
The Britain-based Syrian Observatory for Human Rights, an activist group, confirmed that mortars struck Mazzeh 86, but said it had no immediate reports of casualties.
On the bombings in Turkey, al-Zoubi said that "no one has the right to make false accusations." He said that "this is not the behavior" of the Syrian government.
Zoubi's comments were the first official Syrian response since Saturday's blasts in the Turkish border town of Reyhanli, near Syria.
The bombings left 46 people dead and marked the biggest incident of violence across the border since the start of Syria's bloody civil war, raising fears of Turkey -- once one of Syria's top allies in the region -- being pulled deeper into the conflict.
The Syrian minister alleged that Turkey is responsible "for all that happened in Syria and what happened in Turkey yesterday," accusing Istanbul of facilitating the entry of "terrorists" to Syria.
The Syrian regime routinely describes rebels fighting to topple Assad as terrorists.
"The Turkish terrorist government is responsible for transforming the border areas into ... centers for international terrorism," he said.
Al-Zoubi also launched one of the harshest personal attacks on Turkey's prime minister by a Syrian official so far, demanding that Recep Tayyip Erdogan "step down as a killer and as a butcher."
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