DAMASCUS, Jan. 8 (Xinhua) -- A truce in the rebel-held water-rich Barada Valley near Damascus has ended Sunday, with military operations resuming after the rebels thwarted negotiations to defuse the situation in that area, the main water source to Damascus, a military source told Xinhua.

The truce, which was established on Thursday, ended after the failure of the negotiations, as the al-Qaida-linked Nusra Front fired, for the second day, at the government maintenance workers, who were poising to enter the valley to fix the water pumps feeding the capital with water.

The faltering truce aimed to give a respite of battles to allow negotiators to conclude an understanding to defuse the explosive situation in that area.

This comes as battles have raged over the past two weeks between the government forces and the rebels, who were accused by the government of cutting off the drinking water from the capital Damascus, as the valley contains Ain al-Fijah springs, the main water source feeding the capital's over five million inhabitants with drinking water.

Previous attempts to reach a truce and understanding between the rebels and the government had failed, which led to a wide-scale military offensive by the Syrian army backed by the Lebanese Shiite Hezbollah group against the area, with the rebels responding by severing the water from Damascus.

As negotiators were inside the valley Saturday morning, government maintenance workers were on standby in the nearby town of Deir Qanun, some 5 km from Barada Valley, to start fixing the Ain al-Fijah springs, which sustained damages as a result of the military showdown near that area.

Later in the day, the state TV said the maintenance workers couldn't enter the area, as they were targeted by rebels' snipers in that area, which led to delaying their entry.

Some activists groups said the rebels will allow the workers to enter Barada Valley on Sunday, but such promises were rendered flat with renewed firing on the workers.

Barada wasn't considered by the government to be part of the a Turkish-Russian sponsored ceasefire that went into force on Dec. 30, as the area is largely controlled by the al-Qaida-linked Nusra Front, which is designated as a terrorist group, and thus excluded from any settlement in Syria.

However, the Nusra fighters there have cut off the water from Damascus since Dec. 22, causing a massive water outage, amid recent reports that water poisoning cases started to surface as people have resorted to unclean water.