Troops shot at protesters Friday in Damascus and Aleppo, the Syrian Observatory for Human Rights said, reporting at least 75 deaths across the country ? 25 civilians, 24 soldiers and 26 rebels.
Protesters had taken to the streets to renew their demands for the fall of the regime under the slogan "Remove Kofi Annan, the servant of [President Bashar al-] Assad and Iran," referring to the UN and Arab League envoy.
In Damascus, "regime troops shot heavy rounds of live gunfire in the Nahr Aysha district to disperse protesters," the Observatory said, adding that demonstrators were also shot at in the Sayida Zainab district.
Three protesters were wounded in Harasta, also in Damascus province, and later several people including a child were wounded when regime forces shelled the town, the Observatory said.
In the northern commercial hub of Aleppo, troops opened fire in a bid to disperse the demonstrations, the Britain-based watchdog said.
Twitter user Syria.Revo reported "massive demonstrations," while online activists said spontaneous protests began on Thursday night, to denounce the killing of some 150 people in Treimsa in the central province of Hama.
In Hama, scores of protesters chanted slogans and carried posters in honor of those killed at Treimsa, according to amateur video posted on YouTube.
Some carried Syrian independence flags amid chants demanding the fall of Assad. Others chanted: "O Treimsa, we are with you to the death."
In Hama, one protester held up a sign reading: "Kofi Annan: There is no longer any room for your initiative, you are the reason for the massacres, and you are the one protecting the Hulago regime with your failed plan," in reference to a 13th century Mongol ruler, grandson of Genghis Khan.
In rebel-held Rastan, scores of people gathered inside a hall as regime forces shelled the besieged town, calling for "the fall of Assad and Annan."
There was also violence elsewhere, including various districts of Damascus, the Observatory said, adding that seven civilians ? including a child ? were killed in the capital on Friday.
In the northwestern province of Edleb, five civilians and 15 rebels were killed in a raid by regime troops.
It is not possible to independently verify death tolls. The United Nations stopped compiling such figures at the end of 2011.
The Observatory has said more than 17,000 people have been killed since the uprising erupted in mid-March last year.
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