BEIRUT (AP) -- Syrian rebels captured the country's largest dam on Monday after days of intense clashes, giving them control over water and electricity supplies for much of the country in a major blow to President Bashar Assad's regime.
The rebels had already seized two other dams on the Euphrates River. But the latest conquest, the al-Furat dam in northeastern Raqqa province, was a major coup for the opposition. It handed them control over water and electricity supplies for both government-held areas and large swathes of land the opposition has captured over the past 22 months of fighting.
Two separate car bombings in northern Syria killed a total of 26 people. Both were blamed on al-Qaida-linked militant group Jabhat al-Nusra.
The rebels have had their biggest success in the civil war across Syria's north including Idlib, Raqqa and Aleppo provinces, all bordering Turkey.
Rami Abdul-Rahman, a Britain-based activist with the group Syrian Observatory for Human Rights, said rebels took control of al-Furat dam around midday after successfully pushing out a group of Assad loyalist from the control room. Most of the regime troops in the area had stopped fighting on Sunday following the fall of the nearby town of al-Thawra, Abdul-Rahman said.
The rebel assault on the dam was led by al-Qaida-linked militant group Jabhat al-Nusra.
The government did not confirm it has lost control of the dam.
Earlier this month, the Observatory said rebels seized another smaller dam in Raqqa province, the Baath dam, named after Syria's ruling party. In November, Syrian opposition fighters captured Tishrin hydroelectric dam near the town of Manbij in northern Aleppo province, which borders Raqqa.
Members of al-Nusra, which the U.S. has branded a terrorist organization, have been among the most effective fighters in the battle to oust Assad. The group had led battles for the other two dams, and was also a decisive force in the opposition's successful attacks on regime army bases outside major cities, including the capital, Damascus, and Aleppo in the north.
The group was also believed to be behind two car bombings on Monday.
One exploded near a border crossing with Turkey in Idlib province. Bulent Arinc, Turkey's deputy prime minister, said 12 people were killed -- nine Syrians and three Turks. He said 28 people were wounded, nine of them Turks. The vehicle that exploded had a Syrian license plate, he added.
Turkey's NTV said most of the victims were Syrians who had been waiting to enter Turkey. It cited Huseyin Sanverdi, mayor of the nearby Turkish town of Reyhanli, as saying the explosion occurred in a "buffer zone," an area straddling the frontier where travelers are processed while crossing between the two countries.
Witnesses said it struck a spot where humanitarian aid is loaded onto Syrian vehicles.
The border area between the two countries has been the scene of fierce fighting in the civil war. Tensions have also flared between the Syrian regime and Turkey in the past months after shells fired from Syria landed on the Turkish side.
As a result, Germany, the Netherlands and the United States decided to send two batteries of Patriot air defense missiles each to protect Turkey, their NATO ally.
In the second car bombing, the Observatory said members of Jabhat al-Nusra blew themselves up in two car bombs outside an intelligence office in the city of Shadadah in the northeastern province of Hasaka, killing at least 14 security agents.
The Observatory said Shadadah has been the scene of heavy clashes between troops and rebels.
Diplomatic efforts to stop the carnage in Syria have failed, leaving the international community at a loss for ways to end the civil war.
Assad presented a plan last month, offering a national dialogue. The opposition rejected it, saying no to talks unless the president relinquishes power.
Former Prime Minister Riyad Hijab, one of the highest ranking officials to defect from Assad's regime, met Arab League chief Nabil Elaraby and asked him to let the Syrian opposition take over the country's seat in the pan-Arab organization.
The Arab League has suspended Syria's membership over its military crackdown against protesters calling for regime change.
Hijab, speaking to reporters, did not say whether Elaraby has agreed to the request and there was no immediate comment by the Cairo-based League.
Assad was quoted by state-run news agency SANA as saying Syria will not give up its principles "regardless of how strong the pressures and conspiracies" are against it.
The report said Assad met in Damascus Monday with John Yazigi, the Eastern Orthodox Patriarch of Antioch.
Associated Press writers Chris Torchia in Istanbul and Ezgi Akin contributed in Ankara, Turkey contributed to this report.