Beirut (AFP) - UN aid has reached the last rebel holdout in the central Syrian city of Homs for the first time in six months, activists and a monitoring group said Thursday.

"On Tuesday and Wednesday, 30 trucks of aid arrived in Waer for the first time in six months," Rami Abdel Rahman of the Syrian Observatory of Human Rights told AFP.

Abdullah al-Homsi, an activist in the rebel-held district, said via the Internet that the trucks brought 20,000 food parcels, sanitary equipment, rain shelters and blankets.

Another activist said in a video message that the vehicles arrived at night and also delivered "detergents, school supplies and gifts from the United Nations".

In May, forces loyal to President Bashar al-Assad recaptured the historic Old City of Homs from rebel fighters, ending a devastating two-year siege of their stronghold.

Under a landmark agreement supervised by the United Nations, a group of rebel fighters pulled out of the city.

But around 150,000 people, including tens of thousands who fled the fighting in Homs, remain confined to the district of Waer, which the Syrian army continues to bombard.

Numerous attempts to reach a truce have failed, with each side accusing the other of hobbling the negotiations.

UN-mediated talks are ongoing between the government and the rebels, according the Britain-based Observatory, but activists have expressed doubts about the regime's intentions.

"We have confidence in the efforts of the UN but we fear the regime is trying to use the UN to retake Waer," said Abdullah al-Homsi.

On Thursday, according to the Observatory, the army shelled Waer, further bolstering the rebels' suspicions.

Homs was once seen as the "capital of the revolution" against the Assad regime.

Over the past year, the outgunned and underfunded rebels have lost a string of bastions across Syria, notably in Homs and Damascus provinces.

Also on Thursday, the air force bombarded the rebel-held village of Saqba east of Damascus, killing at least nine civilians including three children and four women, according to the Observatory.

"The regime is trying to reclaim the (rebel-held, besieged) Eastern Ghouta area east of Damascus, and there are air strikes there every day," said Abdel Rahman.

"But most of the casualties, every time, are civilians," he added.