Syrian opposition forces on Saturday retook a strategic mountaintop in the coastal Latakia province, activists said, hours after the United Nations endorsed a plan for political transition in the war-ravaged country in a rare sign of unity among world powers.The Syrian Observatory for Human Rights reported that fighters regained control of Jabal al-Nuba north east of Latakia, days after losing the hilltop to troops of Syrian President Bashar al-Assad.At least 18 regime forces and allied militias were killed in the opposition forces' attack in the area, the Britain-based Observatory reported.It added that an unspecified number of opposition fighters were also killed in the battles that pitted al-Assad's troops, backed by fighters from the allied Lebanese Shiite Hezbollah, against extremist groups, including the al-Qaeda-linked al-Nusra Front.The hilltop is strategically important because it overlooks the rebels' supply lines between Latakia and the northern province of Aleppo.On Wednesday, the Syrian army announced having taken control of Jabal al-Nuba.Syria's conflict, which started in 2011, has drawn a motley of foreign fighters to the country, raising international concerns that Syria is turning into a hub for extremist groups.The Daesh terrorist militia, which rules large parts of Syria, has claimed a series of deadly attacks around the world in recent months.On Friday, the UN Security Council unanimously passed a resolution espousing a plan for a peace process in Syria, calling for regime-opposition negotiations to begin in January and tasking the UN with aiding the implementation and monitoring of a nationwide ceasefire there.The resolution rubber-stamped a plan agreed in Vienna last month that would lead to the establishment of a transitional government in Syria within six months and new elections within 18 months.The resolution made no mention of the fate of al-Assad, a main sticking point among major powers.Russia and Iran, al-Assad's main allies, refuse any agreement that would force him to step down, while the US and other countries backing the rebels want him out of power.