Syrian President Bashar al-Assad has told visiting UN-Arab League envoy Kofi Annan that no political dialogue can succeed in his country while "armed terrorist groups" are operating.
Mr Assad said Syria would back "any honest effort to find a solution".
The UN said Mr Annan's task was to call for an immediate ceasefire by the army and the opposition.
Fighting on Saturday left 63 people dead, activists say, in a report which could not be verified independently.
Most of the deaths reported by the Local Coordination Committees (LCC) were in the Idlib area of the north-west, where the army was said to be shelling the city of the same name.
The UN says more than 7,500 people have died since the violence began nearly a year ago.
Earlier, UN humanitarian chief Valerie Amos said "limited progress" had been made on aid but much more was needed.
Calls for reform that began with pro-democracy protests a year ago have degenerated into violence that has brought Syria to the brink of civil war.
'All violence must stop'
Mr Annan's talks with Mr Assad lasted for more than two hours, after which Mr Annan met Foreign Minister Walid al-Moallem over lunch.
The meetings were held in a "positive" atmosphere, Syrian state television said.
Mr Assad said: "Syria is ready to make a success of any honest effort to find a solution for the events it is witnessing.
"No political dialogue or political activity can succeed while there are armed terrorist groups operating and spreading chaos and instability."
The BBC's Lina Sinjab in Damascus says this is a clear message that the military operation, and violence, will continue.
The Syrian Observatory for Human Rights, another activists' group, said the shelling of Idlib was the heaviest since army reinforcements arrived earlier in the week. The Observatory said the bombardment was an apparent prelude to a ground assault, as happened in the city of Homs.
One activist in Idlib told Reuters news agency by telephone that government tanks were entering the city.
The Associated Press news agency reported families fleeing the violence with their belongings.
UN Secretary General Ban Ki-moon said earlier he had asked Mr Annan to pursue an immediate ceasefire in Syria.
If a ceasefire could not be agreed simultaneously, then government troops should stop first, followed by the opposition, he argued.
Mr Annan, who is due to meet Mr Assad again on Sunday, is expected to also seek talks with opposition figures before he leaves.
Coinciding with Mr Annan's arrival, a meeting of Arab League foreign ministers has been taking place in Cairo, attended by Russian Foreign Minister Sergei Lavrov.
The BBC's Jon Leyne in Cairo says the meeting has revealed bitter divisions between the League and Moscow, with Russia finding out just how little support its policy on Syria has.
Mr Lavrov warned against "crude interference" in Syria's internal affairs, insisting that Russia was not "protecting any regimes.
The Qatari delegation said it was time to send Arab and international forces in to Syria, as there was a "moral and humanitarian obligation to stop the daily systematic killing there".
Nevertheless, a final joint statement set out several points of agreement, including the rejection of foreign intervention in the conflict-stricken country.
Ministers also agreed on the need for a mechanism to objectively monitor the situation and the need to deliver humanitarian aid.