Syrian troops have assaulted the village of Sarjeh in the north-west province of Idleb, activists said. The attack was the latest military operation in the area as President Bashar al-Assad tries to quash dissent a week before Ramadan, when protests are expected to intensify.

Forces backed by tanks entered the village, electricity and water supplies were cut off and arrests made, the local co-ordinating committees reported. Activists also reported reinforcements entering Homs, the flashpoint city north of Damascus that was the focus of an increased crackdown last week, and a campaign of detentions in Damascus.

Arrests in Damascus focused on the Rukn ad-Deen and Qaboun neighbourhoods, activists said, where protests have increased over the past fortnight.

Protests have disrupted satellite villages around the capital since the beginning of the uprising, now in its fifth month, but have been creeping closer to the centre in recent weeks.

In Harasta, close to the city centre, several protesters who claimed to have been beaten by security forces after demonstrations on 15 July revealed purple eyes and limbs and backs covered in bruises. "We will carry on protesting and try to move into the centre," said one, who claimed he was taken on board a bus then beaten with an iron bar by security forces.

Activists have called this week the "week of detainees" to highlight more than 10,000 people estimated to be held, as a group of Palestinians from Yarmouk camp in Damascus warned that they would join protests after several people were detained in the area.

"We considered what is happening in Syria is a domestic issue … but our neutrality will not persist in the presence of ongoing security campaign and arrests," said a statement posted on the local co-ordinating committees' facebook page.

The crackdown against protesters in which more than 1,500 civilians have been killed drew further criticism after the latest Friday of protests in which 11 more people were shot dead. UN officials spoke of the "serious possibility" of crimes against humanity having been committed in Syria, while the British foreign secretary, William Hague, condemned the regime for stirring sectarian tensions.

"President Assad claims that he is holding Syria's different factions together but his regime's brutal violence in Homs and other cities risks inflaming these tensions," Hague said.

Nour Ali is a pseudonym for a journalist in Damascus