Syria opposition declares new battle against Assad after Aleppo attacks

Several of Syria's key opposition factions said on Monday they were launching an armed response to what they alleged were Syrian government "violations" of a ceasefire agreement in the war-torn country. 

"After the increase of violations by regime forces that included targeting displaced people and continuous bombing of residential neighbourhoods, we declare the start of the battle in response," said a statement signed by 10 armed rebel groups.

The truce, brokered by Russia and the United States, has seen violence dip significantly across Syria but fighting has recently flared in several regions, particularly around the second city Aleppo. 

Fighting in Aleppo killed at least 22 civilians at the weekend prompting opposition groups to threaten to quit Syria peace talks in Geneva if there is no progress on a political transition.

A barrage of rockets and sniper fire by opposition groups onto government-controlled western districts killed 16 civilians, including 10 children and two women.

The attacks came after at least six civilians were killed and eight wounded in government air strikes on rebel-held eastern parts of the city on Saturday. 

The Syrian Observatory for Human Rights said the number of civilians killed in Aleppo city was one of the highest single tolls since a fragile truce came into force on 27 February.

"There's a clear escalation. This was the bloodiest incident in Aleppo and its province" since the ceasefire began, Observatory head Rami Abdel Rahman said.

"This escalation directly threatens the truce."

The opposition High Negotiations Committee said the indirect negotiations could collapse if Syria's government refuses to compromise on political and humanitarian issues.

"We might suspend [our participation in] the talks if things carry on this way, and then there will be no prospect for any political solution," HNC member Abdulhakim Bashar said.

Nearly all warring parties in Syria - the government, rebels, militants and Kurds - have carved out zones of control in war-torn Aleppo province.

The HNC has questioned the government's commitment to a political solution to Syria's five-year war, particularly in the wake of the renewed violence in Aleppo.

"The humanitarian situation is continually deteriorating, the issue of the detainees has not seen any progress, the ceasefire has almost collapsed, and now there is an attack on Aleppo from three sides," Bashar said in Switzerland.

"Given these factors, we are reviewing everything, and we will continue our meetings today [Sunday] so that tomorrow we can decide what to do."

Talks nearly at 'impasse'

A second member of the HNC delegation, speaking anonymously, said the talks were nearly at "an impasse".

"The negotiations have nearly reached an impasse with the intransigent regime's refusal to negotiate the fate of [President Bashar al-] Assad in the Geneva talks," the member said.

Assad's fate has remained the main sticking point in peace talks, with Syria's opposition clinging to its call to depose him since the conflict broke out in 2011.

But the government has rejected the embattled leader's departure, calling his fate "a red line".

In Tehran, EU foreign policy chief Federica Mogherini used her discussions with Iranian Foreign Minister Javad Zarif and National Security Chief Ali Shamkhani to press Iran to push Damascus into a political process that could end in constitutional reform and free elections after five years of bloodshed, the Wall Street Journal reported.

“Iran has not only a lot of influence in Damascus still but also a deep knowledge of the regime that can help the international community to find formulas that could be useful to have a political process that is successful,” Mogherini told a small group of journalists on Saturday evening.

The peace plan outlined by UN envoy Staffan de Mistura and backed by world powers envisions a political transition, a new constitution, and presidential and parliamentary elections by September 2017.

But Syria's government hosted its own regularly scheduled parliamentary elections last week, which Assad's ruling Baath party easily won. 

As expected, the Baath party and its allies won a majority of the 250 parliamentary seats in a vote that only took place in government-held parts of the country.

The election was denounced by the opposition as a "farce".

In Geneva on Sunday, the chief negotiator of the HNC delegation called for renewed attacks on government forces, despite the shaky truce.

"Don't trust the regime and don't wait for their pity," Mohammed Alloush, a leading political figure in the Jaish al-Islam [Army of Islam] rebel group, wrote on Twitter. 

"Strike them at their necks [kill them]. Strike them everywhere," he said.

A fellow opposition figure said Alloush's hawkish statement did not represent the HNC's position. 

Brokered by Russia and the United States, the ceasefire agreement to cease hostilities excludes the fight against the Islamic State group or al-Qaeda's affiliate in Syria.

The truce had largely held across parts of Syria since late February, despite frequent accusations of breaches on both sides.

But recent violence has sparked concerns the ceasefire may peter out, partly because rebels are involved in the battles too.

The Islamic State group has seized fresh territory from rebel groups in Syria's north, threatening the key opposition town of Azaz, just eight kilometres south of the Turkish border.

The onslaught has forced 30,000 Syrians to flee, and tens of thousands more are at risk of displacement.

Since the Syrian conflict erupted in 2011, half of the country's population has been displaced - including five million who have fled to neighbouring states.

More than 270,000 people have been killed.