By Khaled Yacoub Oweis
AMMAN (Reuters) - Protesters across Syria demanded President Bashar al-Assad's removal after prayers marking the end of the Muslim fasting month of Ramadan, defying tanks and troops besieging many cities and towns, activists and residents said.
Security forces shot dead at least four demonstrators, including a 13-year-old boy, as they streamed out of mosques in the towns of al-Hara and Inkhil in southern Deraa province.
Demonstrations broke out elsewhere across the country, especially in Damascus suburbs, the city of Homs, 165 km (100 miles to the north) and the northwestern province of Idlib, activists and residents said.
"The people want the downfall of the president," shouted protesters in the Damascus suburb of Harasta, where activists said dozens of soldiers defected at the weekend after refusing to shoot at protesters.
In the adjacent suburb of Saqba a crowd held their shoes up in the air -- an insulting gesture in the Arab world -- and chanted "This is your level Bashar."
According to one activists' group, troops have killed at least 551 civilians during Ramadan, the holiest period in the Islamic calendar.
Five months into the street uprising against his autocratic rule, Assad, from Syria's minority Alawite sect, is facing more frequent demonstrations, encouraged by the demise of Muammar Gaddafi's rule in Libya, with whom Assad had close ties, and rising international pressure on the ruling hierarchy.
Residents and activists have also reported increasing defections among Syrian troops, drawn mostly from the Sunni majority population but dominated by Alawite officers effectively under the command of Assad's younger brother Maher.
In the capital, YouTube footage showed soldiers from core units roaming the center in big green public transport buses, their AK-47s hanging out from bus doors, to prevent protests, which broke out nonetheless in Qaboun, Kfar Souseh, Rukn al-Din and Maydan districts, activists said.
In a report published on Tuesday, the Syrian Revolution Coordinating Union grassroots activists' group said Assad's forces killed 551 people during Ramadan and that 130 others were killed on July 31, the eve of Ramadan, in a tank assault on the city of Hama, scene of a 1982 massacre by the military.
"The report does not include the number of martyrs who were not identified by name nor... bodies that were abducted (by security forces) and not returned to their families," it said.
The official state news agency said state television had aired an audio recording of two "terrorists" who described themselves as activists. It said the tape revealed "a full agenda of provocation and targeting police and army camps and terrorizing peaceful citizens in the name of freedom and non-violence."
The Syrian National Human Rights Organization, headed by exiled dissident Ammar al-Qurabi, said pro-Assad forces, including a loyalist militia known as shabbiha, had killed at least 3,100 civilians since the uprising erupted in March, including 18 people on Monday alone.
Syrian authorities blame "armed terrorist groups" for the bloodshed and say they have killed 500 soldiers and police.
In the town of Rastan near the city of Homs on Monday, and armored force of Assad loyalists surrounded a town and fired heavy machineguns after the defection of tens of soldiers in the area, activists and residents said.
One woman, 45-year-old Amal Qoraman, was killed and five other people were injured, they said, adding that tens of people were arrested in house-to-house raids in the town of 40,000.
Syrian authorities have repeatedly denied that army defections have been taking place. They have expelled independent media since the uprising began in March.
European Union governments may impose sanctions on Syrian banks as well as energy and telecommunications companies within a week, along with a planned embargo on oil imports from the country, EU diplomats said on Monday.
(Additional reporting by Suleiman al-Khalidi; Editing by Kevin Liffey and Elizabeth Fullerton)