There are concerns about the durability of a nationwide ceasefire in Syria after government forces and their allies clashed with rebels.

The fresh fighting could put the truce - brokered by Russia and Turkey and agreed between President Bashar al Assad's regime and opposition fighters - under pressure.

Helicopter gunships were reportedly used to attack groups, including the Fateh al Sham Front, in Wadi Barada, a rebel-held valley northwest of the capital Damascus.

The government said the al Qaeda affiliate, previously known as al Nusra Front, was excluded from the truce, which came into force at midnight on Thursday.

But the opposition said it believed the ceasefire applied to all of Syria, including areas where Fateh al Sham was present.


A spokesman for Fateh al Sham Front criticised the ceasefire for not declaring the fate of Syria's president Bashar al Assad.

In a statement, the unidentified spokesman said: "The solution is to topple the criminal regime militarily".

Syrian government agrees ceasefire with rebels

Islamic State and the Kurdish YPG militia have also been excluded from the ceasefire deal.

It is not clear which side started the latest clashes in a country where repeated international efforts towards peace have failed.

The army began an offensive last week to retake Wadi Barada, which provides most of Damascus' water supplies.

The military has accused rebels of deliberately targeting the infrastructure there.

Government warplanes have also carried out airstrikes in the central province of Hama, according to monitors.

Meanwhile, Russian fighter jets have hit three IS targets around the northern town of al Bab over the past 24 hours, according to Turkey's military.

Ceasefire agreement is 'fragile' and needs 'special attention'

The action could be the first Russian support for Turkish army operations in the area.

The ceasefire, backed by Assad ally Moscow and opposition-supporting Ankara, has appeared to have mostly held elsewhere.

It is designed to pave the way for a political solution to a conflict that has claimed more than 310,000 lives since it began with anti-regime protests in March 2011.

Despite backing opposing sides in the war, Moscow and Ankara are pushing for talks between Damascus and the rebels to begin next month in Kazakhstan.