Turkey has accused the Syrian regime of violating a fragile ceasefire in the country and said the new round of negotiations to be held in Kazakh capital Astana was at risk.

The Russian-Turkish brokered ceasefire last week has brought calm to large parts of Syria, but has been threatened by ongoing fighting in the Wadi Barada region near the capital Damascus.

Turkish Foreign Minister Mevlut Cavusoglu on Wednesday urged the Syrian regime and its backers to end their "violations" of the truce, warning they were jeopardizing the planned talks to be held in Astana this month.

"If we do not stop the increasing violations, the Astana process could fail. After the ceasefire, we see violations," Cavusoglu told the state-run Anadolu news agency.

Syrian regime forces backed by Lebanon's armed Hezbollah group are fighting to recapture Wadi Barada, the main source of water to Damascus.

Cavusoglu urged Russia and Iran, which both back Bashar al-Assad and are also helping prepare the Astana talks, to pressure Damascus and Hezbollah to stop the fighting.

Despite the call, fighting continued on the ground in Wadi Barada on Wednesday, the UK-based Syrian Observatory for Human Rights, a monitoring group, said.

It reported ongoing clashes as well as government air strikes and artillery fire in the area, but had no immediate details on casualties.

Syria's main opposition groups said on Tuesday they have already frozen their participation in the preliminary peace talks due to what they called several "violations" by the regime of the truce that came into effect last week.

"The regime and its allies have not stopped shooting and have launched major and frequent violations, notably in the regions of Wadi Barada and Eastern Ghouta," the groups said in a joint statement.

Water supply damaged

Wadi Barada has been under regime siege since 2015, but regime forces upped the pressure on the region several weeks ago as they tried to secure a "reconciliation deal" with opposition forces there.

The regime has reached a series of such deals with opposition forces around Damascus in recent months, offering opposition safe passage to other parts of the country in return for their surrender.

The UK-based Observatory said about 1,000 civilians - all of them women and children - fled the fighting in Wadi Barada over the weekend, moving to other parts of the province.

PHOTO CAPTION

Turkish Foreign Minister Mevlut Cavusoglu

Al-Jazeera