Syrian government troops fought deadly battles with armed rebels on Monday as the European Union pushed for an end to a split with Russia over how to end the 15-month bloodshed.
In talks in Saint Petersburg with Russian President Vladimir Putin, EU President Herman Van Rompuy said the EU and Russia "might have some divergent assessments" of the situation in Syria.
But he said they agreed that implementing the troubled peace plan brokered by UN-Arab League envoy Kofi Annan was the only way forward in a situation that risks developing into full-scale civil war.
Government forces attacked rebel strongholds in Idlib province in the northwest and Deir Ezzor in the northeast as violence nationwide claimed nine lives on Monday, the Syrian Observatory for Human Rights said.
The Britain-based watchdog said that the fighting in Idlib's Jabal al-Zawiya hill district, in which two rebel fighters were killed, was the most intense since the uprising against President Bashar al-Assad's regime erupted in March last year.
In Deir Ezzor, the government deployed helicopters to strafe suspected rebel hideouts in farmland in the Sbeikhan district and one was hit by rebel fire, the Observatory said.
The fighting came a day after Assad vowed to crush the rebel Free Syrian Army (FSA), which announced on Friday that it was resuming "defensive operations" because of the failure of a UN-backed ceasefire that was supposed to go into effect from April 12.
The Syrian Observatory said 19 soldiers, eight rebels and 19 civilians were killed in violence across the country on Sunday.
On Saturday, 57 soldiers were killed nationwide, the biggest single day losses for the military of the uprising, the watchdog said.
In Saint Petersburg, Van Rompuy said the EU and Russia fully agreed that the Annan plan provided the “best opportunity to break the cycle of violence in Syria, avoiding a civil war and finding a peaceful, lasting solution."
"We need to combine our efforts in order for this to happen and to find common messages on which we agree," he said.
Van Rompuy had been expected to press Putin to harden his line against Assad's regime.
International frustration with the Kremlin's stance on Syria is growing again after Russia refused to squarely blame Assad for the massacre of more than 100 people in Houla last month, instead saying rebels shared some of the responsibility.
Annan has himself expressed mounting frustration at the slow progress in implementing his peace blueprint.
The former UN chief has agreed to travel to Washington on Friday "to discuss next steps in his six-point plan and in particular political transition" in Syria, a senior State Department spokeswoman said.
Arab League chief Nabil al-Arabi is to head to the United Nations later this week to press for swifter implementation of the Annan plan, a League official said.
"Arabi's four-day visit, starting on Thursday, will focus on the Syrian crisis and on efforts to convince the UN Security Council of the need for an urgent solution," the official said.
Arab ministers at a meeting on Saturday in Doha urged the United Nations to refer Annan's peace plan for Syria to Chapter VII, without explicitly calling for military action.
Chapter VII outlines action the UN Security Council might take, including military force, in response to threats to international peace, breaches of the peace and acts of aggression.
The Council "must honour its responsibilities, in accordance with the UN Charter, and take the necessary measures to guarantee the full and immediate implementation of the Annan plan, in a limited time frame," the ministers said.
Annan himself has demanded a "serious review" of deadlocked efforts to end the bloodshed and is stepping up pressure on international powers to put some muscle into their support for his peace plan or find a Plan B, diplomats said in New York.
As many as 2,400 of the more than 13,500 people killed since the uprising began have died since the UN-backed ceasefire began on April 12, according to the Syrian Observatory for Human Rights.
"The time is coming, if it is not already here, for a serious review," Annan told Arab League ministers in Doha.
