DAMASCUS  - International peace envoy Lakhdar Brahimi warned after meeting President Bashar al-Assad on Saturday that the worsening conflict in Syria threatens both the region and the world at large.

Russia, a strong ally of Syria, insisted it was not "clinging" to any particular leader in Syria, but warned it would block any new UN Security Council resolution aimed at pressuring Assad, a long-time Moscow ally.

"The crisis is dangerous and getting worse, and it is a threat to the Syrian people, the region and the world," said the newly appointed Brahimi, who took over as envoy earlier this month from former UN chief Kofi Annan.

Assad, quoted by state television, said dialogue between Syrians held the key to a solution and called on foreign countries to stop supplying arms to his foes. "The real problem in Syria is that of combining politics with the work being done on the ground," he said. "The political work continues, in particular by calling for dialogue between Syrians based on the aspirations of all Syrians.

"The success of political action is dependent on putting pressure on the countries that finance and train the terrorists, and which bring weapons into Syria, until they stop doing so," Assad said. Eighteen months into Syria's deadly conflict and without an end in sight, Assad said his government would "cooperate with all sincere efforts to solve the crisis, so long as the efforts are neutral and independent."

Brahimi, a 78-year-old veteran Algerian troubleshooter, has also met Foreign Minister Walid Muallem and members of the officially tolerated opposition since arriving in Damascus on Thursday. "There is need for all parties to unite their efforts to find a solution for the crisis, given Syria's strategic importance... and the crisis's influence over the whole region," Brahimi said.

"The solution can only come from the Syrian people."

He said he currently had "no plan" to tackle the crisis, but a strategy will be "set... after listening to all internal, regional and international parties."

Brahimi warned on arrival that the conflict is "getting worse." He is on his first Damascus visit since replacing Annan who quit after a hard-sought peace deal he brokered became a dead letter. Brahimi on Friday met Syrian opposition figures who said he was bringing "new ideas" to the peace effort.

Pope Benedict XVI, on a visit to neighbouring Lebanon, had words of praise for young Syrians on Saturday.

"I want to tell you how much I admire your courage," the 85-year-old pontiff said, but added that he was "sad because of your suffering and your bereavement."

The Syrian Observatory for Human Rights, which gathers information from a network of activists on the ground, said at least 48 people, mostly civilians, were killed nationwide on Saturday. It said 132 died on Friday, including 100 civilians, 18 of them in Damascus.

On the ground, overnight air strikes killed at least 12 civilians and wounded around 60 in Al-Bab in northern Syria, doctors in the rebel-held town told AFP.

Two fighter jets carried out a series of raids on the town between 4pm on Friday and 4am on Saturday, hitting homes and empty school buildings, a hospital doctor said, asking not to be identified. In one home four people lost their lives, three of them women, the father of one of those killed told AFP. Residents said there were no rebels in any of the buildings hit. Clashes also broke out on Saturday in Damascus and the northern city of Aleppo. In Aleppo the army battled rebels at entrances to the rebel-held Bustan al-Basha district and helicopter gunships attacked the opposition bastions of Hanano and Sakhur, the Observatory said.

Near Damascus, five rebels were killed by shelling and sniper fire in the southern suburb of Al-Hajar al-Aswad, the Observatory said.

Three civilians, including two women, were killed in shelling in the northwest province of Idlib, while in the eastern city of Deir Ezzor a 14-year-old was killed in shelling and the town of Albu Kamal came under fresh bombardment, it said.

Hollywood star Angelina Jolie met Foreign Minister Hoshyar Zebari on Saturday to discuss measures to care for Syrian refugees in Iraq, the foreign ministry said.

They discussed "the situation of Syrian refugees in Iraq and steps taken by the Iraqi government to ensure a decent life for them," the ministry said.

Zebari said Iraq was hosting more than 20,000 Syrians who fled the bloodshed in their country. The UN High Commissioner for Refugees says the number of Syrian refugees in neighbouring countries have exceeded 250,000. Jolie, a special UN envoy, will head Sunday to Arbil, the capital of northern Iraq's autonomous Kurdistan, to meet Syrian refugees housed in camps at Dohuk, 400 kilometres (250 miles) from Baghdad. Before travelling to Iraq, Jolie already visited Syrian refugees in Jordan, Lebanon and Turkey.