Washington roundly denied the charge and accused the Syrian embassy in Washington of spying on demonstrators in the United States.
Opposition activists reported five deaths on Friday in the central city of Homs, two in the capital's commercial neighbourhood Medan, six in the Dmeir area, east of Damascus, and two in the Maaret al-Numan area of the northwest.
The Syrian Observatory for Human Rights said security forces also arrested more than 200 people nationwide on Friday, more than half of them in Homs.
Rights groups say security forces have killed more than 1,300 civilians and arrested at least 12,000 since anti-government protests erupted in mid-March.
New York-based Human Rights Watch issued a damning criticism of Syrian security forces for firing on unarmed civilians and for beating detainees, based on testimony from alleged defectors.
"All of the interviewed defectors told Human Rights Watch that their superiors had told them that they were fighting infiltrators (mundaseen), salafists (Muslim fundamentalist radicals) and terrorists," HRW said in a statement.
"The defectors said they were surprised to encounter unarmed protesters instead, but still were ordered to fire on them in a number of instances. The defectors also reported that those who refused orders to shoot on protesters ran the risk of being shot themselves."
One defector spoke of an incident in Homs, where "protesters had sat down in the square."
"We got an order... to shoot at the protesters. We were shooting for more than half an hour. There were dozens and dozens of people killed and wounded.
"Thirty minutes later, earth diggers and fire trucks arrived. The diggers lifted the bodies and put them in a truck. I don't know where they took them."
The London-based Syrian Observatory's director Rami Abdel Rahman said 450,000 Syrians rallied after Friday prayers in Hama, an opposition bastion, under the banner "No to dialogue" with Assad's regime and called for its ouster.
On Saturday, the military moved into the Jebel al-Zawiya region of Idlib province in northwest Syria, Abdel Rahman said.
"Soldiers supported by 27 tanks, transports and a crane assaulted Kafarhaya in Jebel al-Zawiya. In searches, they ransacked the houses of wanted activists," he said, adding that computers and mobile phones were confiscated.
Both US envoy Robert Ford and French ambassador Eric Chevallier visited Hama on Thursday.
Damascus accused Ford of meeting "saboteurs" and inciting people to violence, but the State Department said he had done no such thing and had gone as an international observer with the regime's knowledge.
The foreign ministry called Ford's presence in Hama "obvious proof of the implication of the United States in the ongoing events, and of their attempts to increase (tensions), which damage Syria's security and stability."
The ambassador met "average Syrian citizens" and "certainly did not incite anyone to anything," US embassy press attache JJ Harder told AFP.
Harder also took issue with government claims that armed gangs are the problem in Hama -- where activists say regime forces have killed 25 people since Tuesday -- stressing that Ford "saw no evidence of this."
Dozens of regime supporters demonstrated outside the American embassy in Damascus on Friday to condemn Ford's trip to Hama, an AFP journalist said.
State news agency SANA said "tens of thousands of people" marched in Damascus, Aleppo -- Syria's second-largest city -- and Deir Ezzor in the east, against foreign intervention and to show their support for Assad's reform programme.
Washington summoned the Syrian ambassador after reports that embassy staff had filmed US protests against the Syria crackdown, the State Department said on Friday.
"We received reports that Syrian mission personnel under ambassador (Imad) Mustapha's authority have been conducting video and photographic surveillance of people participating in peaceful demonstrations in the United States," it said.
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Opposition activists reported five deaths on Friday in the central city of Homs, two in the capital's commercial neighbourhood Medan, six in the Dmeir area, east of Damascus, and two in the Maaret al-Numan area of the northwest.
The Syrian Observatory for Human Rights said security forces also arrested more than 200 people nationwide on Friday, more than half of them in Homs.
Rights groups say security forces have killed more than 1,300 civilians and arrested at least 12,000 since anti-government protests erupted in mid-March.
New York-based Human Rights Watch issued a damning criticism of Syrian security forces for firing on unarmed civilians and for beating detainees, based on testimony from alleged defectors.
"All of the interviewed defectors told Human Rights Watch that their superiors had told them that they were fighting infiltrators (mundaseen), salafists (Muslim fundamentalist radicals) and terrorists," HRW said in a statement.
"The defectors said they were surprised to encounter unarmed protesters instead, but still were ordered to fire on them in a number of instances. The defectors also reported that those who refused orders to shoot on protesters ran the risk of being shot themselves."
One defector spoke of an incident in Homs, where "protesters had sat down in the square."
"We got an order... to shoot at the protesters. We were shooting for more than half an hour. There were dozens and dozens of people killed and wounded.
"Thirty minutes later, earth diggers and fire trucks arrived. The diggers lifted the bodies and put them in a truck. I don't know where they took them."
The London-based Syrian Observatory's director Rami Abdel Rahman said 450,000 Syrians rallied after Friday prayers in Hama, an opposition bastion, under the banner "No to dialogue" with Assad's regime and called for its ouster.
On Saturday, the military moved into the Jebel al-Zawiya region of Idlib province in northwest Syria, Abdel Rahman said.
"Soldiers supported by 27 tanks, transports and a crane assaulted Kafarhaya in Jebel al-Zawiya. In searches, they ransacked the houses of wanted activists," he said, adding that computers and mobile phones were confiscated.
Both US envoy Robert Ford and French ambassador Eric Chevallier visited Hama on Thursday.
Damascus accused Ford of meeting "saboteurs" and inciting people to violence, but the State Department said he had done no such thing and had gone as an international observer with the regime's knowledge.
The foreign ministry called Ford's presence in Hama "obvious proof of the implication of the United States in the ongoing events, and of their attempts to increase (tensions), which damage Syria's security and stability."
The ambassador met "average Syrian citizens" and "certainly did not incite anyone to anything," US embassy press attache JJ Harder told AFP.
Harder also took issue with government claims that armed gangs are the problem in Hama -- where activists say regime forces have killed 25 people since Tuesday -- stressing that Ford "saw no evidence of this."
Dozens of regime supporters demonstrated outside the American embassy in Damascus on Friday to condemn Ford's trip to Hama, an AFP journalist said.
State news agency SANA said "tens of thousands of people" marched in Damascus, Aleppo -- Syria's second-largest city -- and Deir Ezzor in the east, against foreign intervention and to show their support for Assad's reform programme.
Washington summoned the Syrian ambassador after reports that embassy staff had filmed US protests against the Syria crackdown, the State Department said on Friday.
"We received reports that Syrian mission personnel under ambassador (Imad) Mustapha's authority have been conducting video and photographic surveillance of people participating in peaceful demonstrations in the United States," it said.
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