Turkey's prime minister, a staunch critic of Syrian President Bashar al-Assad's regime, on Tuesday called Israel's recent airstrikes in Syria "unacceptable." Recep Tayyip Erdogan made the statement in the capital, Ankara, during a Justice and Development Party group meeting in parliament. "The air attack by Israel on Damascus is unacceptable. No rationale, no reason can excuse this operation. These attacks are a bargaining chip, an opportunity delivered on a silver platter to the hands of Assad, to the illegitimate Syrian regime," he said. The heightened tensions come amid questions about the possible use of chemical weapons in Syria and international debate over how to respond to the country's bloody civil war, in which more than 70,000 people have died in more than two years of fighting. In the latest unrest, U.N. peacekeepers have been seized in Syria near the Israeli-held Golan Heights, a U.N. spokesman said Tuesday. The four were on patrol near al Jamlah, Syria, when an armed group detained them. Officials were working "to secure their safe release," the spokesman said. The Yarmouk Martyrs Brigade, part of the rebel Free Syrian Army, said the peacekeepers were caught in the crossfire between Syrian armed forces and FSA fighters. That prompted the brigade to extract the peacekeepers for their security, the brigade command said. The peacekeepers, all members of a Philippine battalion of the U.N. Disengagement Observer Force, were seized near al Jamlah, in an area that's technically part of the Syrian Golan. After the 1973 war, the force was established to supervise a cease-fire and disengagement agreement. As for Israel, it conducted strikes against Syria twice in recent days, a U.S. official confirmed Monday. One targeted a weapons storage site containing missiles and another was directed at a Damascus research facility, the official said. The official stressed that Israel is concerned about Syria transferring weapons to the Lebanese militant group Hezbollah. The strikes killed 42 Syrian soldiers, the opposition Syrian Observatory for Human Rights said Monday, citing medical sources. It said 100 people remained missing. An Israeli general who commands forces on the Syrian border said "there are no winds of war," according to the Israel Defense Forces website. But the Syrian government warned that Sunday's apparent strikes, which followed one last week that Syria also blames on Israel, open "the door wide for all the possibilities." And Syrian ally Iran warned of a "crushing response," while Russia called reports of Israeli involvement "very worrying."