A senior US official, speaking on condition of anonymity, said Ambassador Robert Ford visited the tense city "to make contact" with opposition leaders.
Syrian authorities have been trying to quell protests in Hama, traditionally a centre of opposition to central government, and had positioned tanks on the main entrances to the city except in the north.
The Syrian Observatory for Human Rights said that about 100 families -- or 1,000 people in total -- had left Hama, where it said Syrian troops had killed 25 civilians since Tuesday.
Observatory chief Rami Abdel Rahman said two civilians were killed on Thursday at Hama.
"Security forces shot them in the legs and then ran them over in their vehicle. They were fatally injured and died on the way to hospital," he said.
The crowds leaving Hama were headed for Salamiyah, some 30 kilometres (18 miles) to the southeast.
Ammar Qorabi, head of the National Organisation for Human Rights, said on Wednesday there had been a worsening of the security situation with the "pursuit of search operations, assassinations and arrests in this city."
Hama has been a symbol of opposition since the 1982 crackdown on a revolt by the banned Muslim Brotherhood against then-president Hafez al-Assad, father of the present leader, in which some 20,000 people were killed.
The newspaper Al-Watan, which is close to the regime, said on Thursday that the situation in Hama was calm and that barricades erected in the streets by protesters had been dismantled.
It reported that the authorities had told demonstrators to avoid any confrontations and clear the streets so residents could go to work and to avoid what it called a "last resort" military operation.
It also said protesters were calling for the former governor to be reinstated, for detained demonstrators to be freed, for a pledge that the security forces would not intervene and for a guarantee of freedom to demonstrate.
Last Friday, an anti-regime rally brought out half a million people in Hama, according to pro-democracy activists. The security services did not intervene and Assad fired the city's governor the next day.
Human rights activists said on Thursday that anti-regime demonstrations took place overnight in several towns in response to a number of pro-regime rallies held on Wednesday.
The activists said thousands demonstrated in the northwest town of Idlib, at Harasta in the southwest and near the southern town of Deraa, while hundreds of protesters rallied in Saqba, a Damascus suburb.
On Thursday, the army slapped a curfew on Jebel Zawiya in Idlib province, a focal point of the military sweep in which 300 people have been detained in the past two days, the Syrian Observatory said.
"The unannounced curfew imposed on the villages of Nasfara, Kfar Awaid, Kfar Ruma and Kfar Nubol prevented residents from meeting their needs," Abdel Rahman said.
"It also prevented farmers from doing their daily work," he added.
Residents of Hama and the central city of Homs staged a general strike ahead of Friday demonstrations, which activists have called under the theme of "no dialogue" with the regime, Abdel Rahman said.
"Dialogue makes no sense if security forces do not pull out of the streets and the regime does not stop its violence against citizens," lawyer Anwar al-Bunni told AFP.
Rights groups say that more than 1,300 civilians have been killed and 10,000 people arrested by security forces since mid-March.
UN chief Ban Ki-moon called on the Syrian president on Thursday to make good on his promises.
"In Syria, meanwhile, the killing continues. This must stop," Ban said in Geneva.
"I call on the Syrian leadership to deliver on its commitments and to allow our UN humanitarian assessment team and the human rights fact-finding mission mandated by the Human Rights Council in.
"It's time to see progress here. We cannot go on like this."
French Foreign Minister Alain Juppe said the UN Security Council's silence because of Moscow's opposition to a resolution condemning Syria was "unacceptable."
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Syrian authorities have been trying to quell protests in Hama, traditionally a centre of opposition to central government, and had positioned tanks on the main entrances to the city except in the north.
The Syrian Observatory for Human Rights said that about 100 families -- or 1,000 people in total -- had left Hama, where it said Syrian troops had killed 25 civilians since Tuesday.
Observatory chief Rami Abdel Rahman said two civilians were killed on Thursday at Hama.
"Security forces shot them in the legs and then ran them over in their vehicle. They were fatally injured and died on the way to hospital," he said.
The crowds leaving Hama were headed for Salamiyah, some 30 kilometres (18 miles) to the southeast.
Ammar Qorabi, head of the National Organisation for Human Rights, said on Wednesday there had been a worsening of the security situation with the "pursuit of search operations, assassinations and arrests in this city."
Hama has been a symbol of opposition since the 1982 crackdown on a revolt by the banned Muslim Brotherhood against then-president Hafez al-Assad, father of the present leader, in which some 20,000 people were killed.
The newspaper Al-Watan, which is close to the regime, said on Thursday that the situation in Hama was calm and that barricades erected in the streets by protesters had been dismantled.
It reported that the authorities had told demonstrators to avoid any confrontations and clear the streets so residents could go to work and to avoid what it called a "last resort" military operation.
It also said protesters were calling for the former governor to be reinstated, for detained demonstrators to be freed, for a pledge that the security forces would not intervene and for a guarantee of freedom to demonstrate.
Last Friday, an anti-regime rally brought out half a million people in Hama, according to pro-democracy activists. The security services did not intervene and Assad fired the city's governor the next day.
Human rights activists said on Thursday that anti-regime demonstrations took place overnight in several towns in response to a number of pro-regime rallies held on Wednesday.
The activists said thousands demonstrated in the northwest town of Idlib, at Harasta in the southwest and near the southern town of Deraa, while hundreds of protesters rallied in Saqba, a Damascus suburb.
On Thursday, the army slapped a curfew on Jebel Zawiya in Idlib province, a focal point of the military sweep in which 300 people have been detained in the past two days, the Syrian Observatory said.
"The unannounced curfew imposed on the villages of Nasfara, Kfar Awaid, Kfar Ruma and Kfar Nubol prevented residents from meeting their needs," Abdel Rahman said.
"It also prevented farmers from doing their daily work," he added.
Residents of Hama and the central city of Homs staged a general strike ahead of Friday demonstrations, which activists have called under the theme of "no dialogue" with the regime, Abdel Rahman said.
"Dialogue makes no sense if security forces do not pull out of the streets and the regime does not stop its violence against citizens," lawyer Anwar al-Bunni told AFP.
Rights groups say that more than 1,300 civilians have been killed and 10,000 people arrested by security forces since mid-March.
UN chief Ban Ki-moon called on the Syrian president on Thursday to make good on his promises.
"In Syria, meanwhile, the killing continues. This must stop," Ban said in Geneva.
"I call on the Syrian leadership to deliver on its commitments and to allow our UN humanitarian assessment team and the human rights fact-finding mission mandated by the Human Rights Council in.
"It's time to see progress here. We cannot go on like this."
French Foreign Minister Alain Juppe said the UN Security Council's silence because of Moscow's opposition to a resolution condemning Syria was "unacceptable."
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