Seven-Day Syria Ceasefire Goes into Effect

The Syrian army, announced the truce at 1600 GMT on Monday,  the moment it took effect, saying the seven-day "regime of calm" would be applied across Syria. It reserved the right to respond with all forms of firepower to any violation by "armed groups".

Militant groups fighting to topple Syrian President Bashar Assad did not immediately declare publicly whether they would respect the ceasefire, but rebel sources said they would do so, despite reservations about a deal they see as skewed in Assad's favor.

A rebel commander in northern Syria said there was "cautious calm" at the start of the ceasefire, Reuters reported. 

The so-called Syrian Observatory for Human Rights, a Britain-based group, said calm prevailed on most frontlines after the ceasefire took effect.

Russia is a major backer of Assad, while the United States supports militant groups fighting to topple him.

The agreement's initial aims include allowing humanitarian access and joint US-Russian targeting of extremist groups, which are not covered by the agreement.

The agreement comes at a time when Assad's position on the battlefield is stronger than it has been since the earliest months of the war. Hundreds of thousands of Syrians have been killed in the conflict and 11 million made homeless in the world's worst refugee crisis.

Hours before the truce took effect, President Assad vowed to take back all of Syria. State television showed him visiting Daraya, a Damascus suburb long held by militants but recaptured last month after fighters surrendered in the face of a crushing siege.

"The Syrian state is determined to recover every area from the terrorists," Assad said in an interview broadcast by state media, flanked by his delegation at an otherwise deserted road junction. Earlier he performed Muslim holiday prayers alongside other officials in a bare hall in a Daraya mosque.

He made no mention of the ceasefire agreement, but said the army would continue its work "without hesitation, regardless of any internal or external circumstances".

The ceasefire is the boldest expression yet of hope by the administration of US President Barack Obama that it can work with Russian President Vladimir Putin to end the war. All previous diplomatic initiatives have collapsed in failure.

The capture of Daraya, a few kilometers from Damascus, has helped the government secure important areas to the southwest of the capital near an air base. The army has also completely encircled the rebel-held half of Aleppo, Syria's largest city before the war, which has been divided into government and opposition-held zones for years.

In the hours before the ceasefire took effect, fighting raged on several key frontlines, including Aleppo and the southern province of Quneitra.

Washington has said the ceasefire includes agreement that the government will not fly combat missions in an agreed area on the pretext of hunting fighters from the former Nusra Front. However, the opposition says a loophole would allow the government to continue air strikes for up to nine days.

Nationalist rebel groups, including factions backed by Assad's foreign enemies, wrote to Washington on Sunday to express deep concerns. The letter, seen by Reuters, said the opposition groups would "cooperate positively" with a ceasefire but believed the terms favored Assad.

It said the ceasefire shared the flaw that doomed the previous truce: a lack of guarantees or monitoring mechanisms. It also said Jabhet Fateh al-Sham should be included, as the group had not carried out attacks outside Syria despite its previous ties to al Qaeda.