Syrian government forces fought fierce clashes with rebels attacking a police academy near the northern city of Aleppo on Friday, while the bodies of 10 men -- most of them shot in the head -- were found dumped along the side of a road outside Damascus, activists said.

Russia, meanwhile, sharply criticized a decision by Western powers to boost their support for Syrian opposition forces trying to topple President Bashar Assad, saying the promised assistance would only intensify the nearly 2-year-old conflict.

Rebels backed by captured tanks have been trying to storm the police academy outside Aleppo since launching a new offensive on the facility last week. The school, which activists say has been turned into a military base used to shell rebel-held neighborhoods in the city and the surrounding countryside, has become a key front in the wider fight for Aleppo.

The Syrian state news agency said Friday that government troops defending the school had killed dozens of opposition fighters and destroyed five rebel vehicles.

The Britain-based Syrian Observatory for Human Rights activist group also reported heavy fighting Friday around the school, and said there were several rebel casualties without providing an exact figure.

Syria's largest city and former commercial hub, Aleppo emerged as a major battleground in the country's civil war after rebels launched an offensive there in July 2012. Since then, the rebels and regime troops have fought street by street for control of Aleppo in a grinding contest that has laid waste to much of the city, considered one of Syria's most beautiful.

The Observatory said clashes were still raging around Aleppo's landmark 12th century Umayyad Mosque in the walled Old City, which is a UNESCO World Heritage Site. The mosque was heavily damaged in October 2012 just weeks after a fire gutted the old city's famed medieval market.

There were conflicting reports about whether the rebels had managed to sweep regime troops out of the mosque and take full control of the holy site.

Mohammed al-Khatib of the Aleppo Media Center activist group said the Great Mosque was indeed in rebel hands, although clashes were still raging in the area.

"The regime forces left lots of ammunition in it (the mosque) with guns and rocket-propelled grenades," he said via Skype.

Observatory director Rami Abdul-Rahman said rebels have been in control of at least half of the mosque for days, but he could not confirm that they now had captured the entire grounds.

The Observatory also said that at least eight people were killed in a government airstrike on the rebel-held Hanano neighborhood of the city. It said three children were among the dead.

The 10 bodies were discovered on a roadside between the Damascus suburbs of Adra and Dumair, said Abdul-Rahman.

All of the bodies were of men who appeared to be between the ages of 30 and 45, he added. One of the men had been decapitated. Their identities were not immediately known.

Such incidents have become a frequent occurrence in Syria's conflict, which the U.N. says has killed at least 72,000 people since March 2011. The conflict has taken on sectarian overtones, and pits primarily Sunni Muslim rebels against Assad's regime, dominated by his Alawite sect, an offshoot of Shiite Islam.

Nearly two years into the Syrian crisis, the regime has lost significant swaths of territory to the rebels, particularly in the northeast near the border with Turkey. But while the rebels control most of the countryside, the Syrian military remains in control of most of the cities.

In a bid to boost the opposition, the Obama administration pledged Thursday at a conference in Rome it will provide non-lethal aid directly to Syrian rebels, while also announcing an additional $60 million in assistance to Syria's political opposition.

In Moscow, Russian Foreign Ministry spokesman Alexander Lukashevich said Friday the moves announced in Rome "in spirit and in letter directly encourage extremists to seize power by force, despite the inevitable sufferings of ordinary Syrians that entails."

Russia is a close ally of Syria, and has continued to supply arms to Assad's regime as well as shielding it from U.N. Security Council sanctions.