Aleppo, Syria: Syrian opposition on Thursday bombarded an air base being used by regime forces to pound the northern city of Aleppo, as a rights watchdog reported 43 people killed in a raid near the capital Damascus.
"Menagh military airport was bombarded on Thursday morning by a tank captured previously by the rebels," the Syrian Observatory for Human Rights said of the base 30 kilometres northwest of the country's commercial capital.
An AFP reporter who heard and saw the bombardment said rebels told him it was "an attack to take this airport being used by helicopters and planes that are firing on Aleppo."
The United Nations confirmed on Wednesday that rebels battling President Bashar Al Assad's regime now had heavy armour, and that its military observers had seen the Syrian military use a fighter jet to attack rebels in Aleppo.
AFP correspondents on the ground have reported that rebels have captured a number of tanks, and some armoured units have defected with their vehicles.
Thursday's air base assault comes after US President Barack Obama was reported to have signed a covert document authorising US support for the rebels.
The directive was contained in a "finding" - a device authorising clandestine action by the Central Intelligence Agency, NBC and CNN said, citing unidentified sources.
White House officials declined to comment on the reports, but did not specifically rule out the idea that Washington was providing more intelligence support to anti-Assad forces than had previously been made public.
The Syrian Observatory said on Thursday a raid by security forces southwest of Damascus killed 43 people, some of whom were tortured and executed.
"Regime forces entered the Jdaidet Artuz district on Wednesday and arrested around 100 young people who were taken to a school and tortured," it said in a statement.
"On Thursday morning after the operation the bodies of 43 people were recovered. Some of them had been summarily executed."
The Observatory had on Wednesday reported 28 civilians killed in the raid.
Al Assad said on Wednesday that the army was fighting for the nation's future as the rebels said they were now turning their sights on the regime's intelligence apparatus in the battle for Aleppo, which has raged since July 20.
Al Assad said the campaign to crush the uprising, now in its 17th month, was vital to Syria's future.
Washington said his call to continue the "slaughter" which human rights monitors say has already killed more than 20,000 people was "despicable."
"The army is engaged in a crucial and heroic battle... on which the destiny of the nation and its people rests," Al Assad said, in a speech carried by the official SANA news agency.