The Old City of Damascus, whose souks were once bustling with shoppers, was swarming with security forces Monday after the regime launched a massive sweep, barging into shops and rounding up residents.
Opposition monitors said government forces had conducted their biggest security operation in the heart of Damascus since President Bashar al-Assad's regime launched its brutal crackdown on protesters 17 months ago.
Checkpoints have been erected across the historic Old City by government forces, as merchants sit idle in their shops in the winding streets of the bazaars.
"This is not the first time there have been raids in central Damascus, but this is the first time something like this has happened on such a large scale," said Rami Abdel Rahman, director of the Syrian Observatory for Human Rights.
The Britain-based Observatory said 22 people had been arrested and that security forces also swept into a graveyard "under the pretext of searching for weapons".
The Syrian Revolution General Council, a network of activists on the ground, said that during the raids armed forces had broken down the doors of shops which had been closed in a show of defiance against the regime.
As security forces raided the Old City and several other districts of the capital, shells slammed into rebel strongholds in Damascus province from before dawn Monday, according to the watchdog.
The Observatory said more than 53 people including 44 civilians had been killed in the past 48 hours in the province of Damascus alone.
On the long cobblestone street of Medhat Pasha in the Old City, numerous checkpoints were set up to inspect cars and identification cards, especially youths, an AFP reporter said.
"On Medhat Pasha there are more than 70 checkpoints," a merchant sighed at his mosaics shop. "I live in Qaboon where the shelling went on all morning. What happens next?"
Nearby, a soldier stopped a man in his early 20s, demanding where he was from. Others passed through the checkpoints, keeping their eyes focused straight ahead.
"They are inspecting the identities of young people, looking for members of the Free Syrian Army," said a linen dealer on Medhat Pasha, referring to the armed rebel group fighting the regime.
He said the security forces were also looking for young people from the central city of Homs, whose rebel-held districts have suffered successive army bombardments, forcing thousands to flee.
Merchants said security forces were also deployed in the souks of Bzouriyeh, Hariqa and Hamidiyeh after taking up positions in several historic houses in the Old City on Sunday.
"Since early morning they stormed the safehouses of the armed men," a jeweller in Hariqa told AFP, adding that the police burst into every house in the area.
Many merchants emptied their storefronts, displaying only some gold bullion to remind people of a safe investment during times of war.
Security forces also carried out raids and arrests in the central Damascus neighbourhoods of Qaimreya, Qashla and Shaghur, the Observatory said.
At least 50 people were killed in across Syria on Monday -- 28 civilians, 13 soldiers and nine rebels -- according to the watchdog.
On Sunday, the death toll reached 150, with the majority in Damascus province, where 26 civilians and seven rebels were killed.
More than 21,000 people have been killed in Syria since the anti-regime revolt broke out 17 months ago, according to the Observatory. The toll is impossible to verify, and the United Nations has stopped maintaining an independent count.