Syrian rebels suffered a deadly blow on Wednesday with 62 of them reported killed, as Amnesty International said parts of second city Aleppo have been devastated.
Government forces killed at least 62 insurgents in an ambush near Damascus, the Syrian Observatory for Human Rights said.
The regime's military said those killed were members of the jihadist Al-Nusra Front.
"At least 62 rebels fell as martyrs, most of them youths, and eight others are missing after an ambush by regime forces at dawn near the industrial city of Adra" northeast of Damascus, the monitoring group said.
A military source quoted by state news agency SANA said the "army carried out an ambush on a group of terrorists belonging to the Al-Nusra Front that was trying to infiltrate Eastern Ghouta and attack a military post".
"All the terrorists were killed and their arms captured," the source added, without giving a toll.
Adra, 35 kilometres (22 miles) from Damascus, is the gateway to Eastern Ghouta, a farming region where a large number of rebels are based.
On July 21, 49 rebels were killed in fighting with loyalist forces in Adra, the Britain-based Observatory said.
Meanwhile, rights group Amnesty International issued a report saying entire neighbourhoods of the northern city of Aleppo have been flattened over the past year, with residents bombed from the air and abused on the ground.
"Aleppo has been utterly devastated, its people fleeing the conflagration in huge numbers," said Amnesty's senior crisis response adviser Donatella Rovera.
The report came as the London-based group released satellite images of several Aleppo districts, taken before and after clashes between government and rebel forces.
The images are part of an Amnesty analysis of the impact of the civil war on the northern city, which was Syria's commercial hub.
They show "alarming trends in how the conflict is being fought: with utter disregard for the rules of international humanitarian law, causing extensive destruction, death, and displacement," Amnesty said.
Aleppo became a battleground in July last year, when opposition fighters in the neighbouring countryside staged an offensive.
Ever since, the city has fallen into a bloody stalemate, with much of eastern Aleppo in rebel hands and the west mostly under army control.
Daily battles are still being waged there, though much of the destruction was the result of "a campaign of indiscriminate air bombardment" by loyalists of President Bashar al-Assad, it said.
Civilians living in opposition-controlled areas suffer daily from both government bombing raids and abuse at the hands of some opposition groups, the report added.
"Countless civilians", it said, have been "killed and maimed" by government bombardments.
"Government forces have relentlessly and indiscriminately bombarded areas under the control of opposition forces across Syria, with civilians being at the receiving end of such attacks and at the same time also being subjected to abuses by some armed opposition groups," said the watchdog.
Many people displaced, especially to areas under rebel control, "receive little or no international aid, partly because they are in dangerous and difficult-to-access areas and also due to restrictions imposed by the Syrian government".
Amnesty reiterated its long-standing demand that the bloodshed in Syria, estimated to have cost more than 100,000 lives over the past 28 months, be referred to the International Criminal Court.
On the economic front, Oil Minister Sleiman Abbas said the government has paid more than $500 million (376 million euros) in subsidies to the oil sector over the past six months.
According to a statement obtained by AFP, Syria is currently producing 39,000 barrels of oil a day. That is down sharply from a figure of 380,000 bpd before the start of the crisis in March 2011.
The government continues to subsidise petrol as well as electricity, rice, sugar and flour.
But because of the war, most oil must be imported, mainly from key regional ally Iran.
Meanwhile, senior US military officer General Martin Dempsey will visit Israel and Jordan next week for a trip focused in part on Iran and Syria, the American military said.