By Weedah Hamzah

Beirut (dpa) - Syrian President Bashar al-Assad needs to be removed from power, the country's opposition said Saturday as it criticized a UN resolution endorsing a Syrian political transition plan because it does not require the president's removal.

The resolution, unanimously adopted by the UN Security Council on Friday, calls for negotiations between al-Assad's government and the opposition to begin in January and tasks the UN with aiding the implementation and monitoring of a nationwide ceasefire in Syria.

However, the resolution made no mention of the fate of al-Assad, a main sticking point among major powers.

"It did not say what al-Assad's fate will be," Ahmad Ramadan, a spokesman for the opposition Syrian National Coalition, said. "The resolution did not talk about the terrorism being carried out by the Syrian regime against its people."

Russia and Iran, al-Assad's main allies, refuse any agreement that would force him to step down, while the United States and other countries back the rebels who want him out of power.

In a rare sign of unity among world powers on Syria's conflict, Friday's resolution also 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 opposition has repeatedly insisted that al-Assad must play no role in Syria's future.

Samir al-Nashar, another member of the Syrian National Coalition, called the UN resolution "unrealistic and difficult to implement."

"I see a lot of mines in it," al-Nashar told dpa.

"First we have to see if al-Assad's regime will stop bombarding the civilians with its barrel bombs," he said, referring to the government's air bombardment of rebel-held areas with barrels packed with explosives.

The indiscriminate weapon is believed to have killed hundreds, including civilians, in Syria.

Al-Assad's government has reacted with caution to the UN resolution, which its ally Russia approved.

"The Syrian government is open to any initiatives or true efforts to help the country get out of the crisis," Syria's UN ambassador, Bashar al-Jaafari, said, according to the official Syrian News Agency SANA.

"Having any successful political track requires the participation of the Syrian government in it as a main partner. So, it is very important to coordinate and cooperate with the Syrian government on different points related to this track."

Major world powers have in recent months stepped up diplomatic efforts to reach a political solution to Syria's strife amid worries that the country has turned into a magnet for hardline jihadists.

The Islamic State terrorist militia, which rules large parts of Syria, has claimed a series of deadly attacks around the world in recent months.

Islamist rebels on Saturday retook a strategic mountaintop in Syria's coastal Latakia province, activists said.

The Syrian Observatory for Human Rights reported that rebels, including some from the al-Qaeda-linked al-Nusra Front, regained control of Jabal al-Nuba north-east of Latakia, days after losing the hilltop to al-Assad's forces.

At least 18 regime forces and allied militias were killed in the rebels' attack in the area, the Britain-based Observatory reported.

It added that an unspecified number of rebels were also killed in the battles that pitted al-Assad's troops, backed by fighters from the allied Lebanese Shiite Hezbollah, against Islamist opposition groups.

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 is estimated to have claimed the lives of more than 250,000 people since it started with pro-democracy protests in March 2011.