With a ceasefire just hours away, a final surge in violence has taken place in Syria. Russian bombers have pounded the capital's suburbs as well as much of the western part of the country that is held by rebels who oppose Syrian President Bashar al-Assad's government.

State media and an opposition monitoring group said that government forces had captured several villages on Friday from extremists belonging to the self-styled Islamic State (IS) in the northern province of Aleppo. The SANA news agency reported that government troops took control of three villages near the town of Khanaser.

Russia unleashed a barrage of airstrikes outside of the capital, Damascus. The planes reportedly fired 60 missiles, including 26 on the town of Douma.

The Syrian Observatory for Human Rights, a UK-based monitoring group, said the air raids were conducted in conjunction with Syrian government artillery fire. Many areas surrounding the capital are held by the "Army of Islam" rebel group.

In all, nearly 100 rebel factions fighting in Syria have agreed to a ceasefire due to take effect Friday at midnight local time (22:00 GMT).

"Factions of the Free Syrian Army and the armed opposition agree to respect a temporary truce ... for two weeks," the High Negotiations Committee said in a statement, referring to 97 rebel factions from the opposition. But mistrust is still running high on all sides.

The Syrian government said it, too, would abide by the truce but vowed to retaliate for any attacks. The opposition is demanding that Russia and Iran, Syria's main backers, also abide by the truce.

Obama under no illusions

US President Barack Obama said the ceasefire would test the commitments of all sides to broader peace negotiations that could lead to a new constitution and free elections.

But he added that he was under no illusions the ceasefire could lead to a total cessation of hostilities.

"We are certain that there will continue to be fighting," Obama said, noting that Islamic State, the Nusra Front and other militant groups were neither party to the negotiations nor the truce. The Nusra Front in particular vowed to continue attacks, rejecting the cessation of hostilities due to begin at midnight.

Leader Abu Mohamad al-Golani said in an audio message on Orient News TV that if Syria's war was not resolved, the consequences would spread to Sunni Muslims in other parts of the region, adding that the truce was a plot which to ultimately keep the Assad government in power.

Russia's state news agency Tass meanwhile quoted President Vladimir Putin saying that the fight against insurgents would "certainly continue."

Russian bomber takes off from Kmeymim airbase in Syria

But US President Obama warned both Putin and Assad that the world would be watching.

Meanwhile German's Foreign Ministry called on all sides to avoid actions that would threaten or undermine the cessation of hostilities.

"We urge all sides to refrain from any actions that might lead to a further escalation and that might potentially threaten the ceasefire," a Foreign Ministry spokeswoman said.

bik, ss/sms (AP, Reuters, AFP)