Syrian town of Rastan 'surrounded by tanks'
Syrian tanks and armoured vehicles have surrounded the town of Rastan, north of Homs, which has been the site of anti-regime dissent, activists say.
In separate operations in the capital and in the northern province of Idlib, at least six people were reportedly killed.
Meanwhile, the opposition has announced a council to lead the uprising.
The UN says more than 2,200 people have died since protests against President Bashar al-Assad began in March.
One of the most influential Sunni clerics, the Sheikh of Al-Azhar in Cairo, has condemned attacks on protesters taking refuge in mosques.
He said the aggressors would be punished in this world and the next.
In Rastan, residents reported heavy machine-gun fire by security forces at the entrance to the town.
Rastan has been caught up in the protests taking place across the country and correspondents say that dissent has continued there despite harsh repression.
"The tanks deployed at both banks of the highway, which remained open, and fired long bursts from their machine guns at Rastan," one resident told Reuters news agency by phone.
Unconfirmed reports from activists say the latest move was prompted by defections among Syrian troops in the area, the agency reports.
Monday's fighting has caused many of the town's inhabitants to flee.
Most foreign journalists have been barred from Syria, making it difficult to verify reports from the country.
Further to the north-west, tanks and troops are reported to have stormed the town of Sarmin, in Idlib province, taking up positions in the central market and firing randomly to keep people off the streets, according to the London-based Observatory for Human Rights.
It said at least five people, including a child, had been killed, and that more than 60 were wounded.
One person died in another raid involving armoured vehicles on Qara, a suburb of the capital, Damascus. About 40 people were arrested there, the group said.
Other attacks were reported near Deir ez-Zor in the east, and around Heet near the Lebanese border in the west. The operation in Heet reportedly sent many civilians fleeing over the border.
Meanwhile, Syrian opposition leaders meeting in the Turkish capital, Ankara, have announced the formation of a Transitional National Council to provide political leadership for the uprising, reports the BBC's Jim Muir in Beirut.
The council will be made up of 94 members, including some leaders still inside Syria and others outside.
It seems to be the most serious attempt so far to unite the opposition on a single platform, but it remains to be seen whether it will gain universal acceptance by all strands of the opposition, especially the activists on the ground, our correspondent adds.
Syria has come under increasing international pressure to end attacks on protesters.
Russian Deputy Foreign Minister Mikhail Bogdanov visited Mr Assad on Monday to deliver a message from Russian President Dmitry Medvedev.
According to a statement on the Russian presidency's website, "the Russian side stressed the need to immediately and fully end violence from any side, to take specific steps to implement the reforms announced by the Syrian leadership without any delay".
It also said "the opposition should not try to evade taking part in dialogue".
A report on state news agency Sana said Russia's position on Syria was "unchanged", and that Moscow had expressed hope that "security and stability would be maintained".
Both the Turkish president and his prime minister have made further outspoken criticisms of the Syrian leadership, saying it is now too late for corrective steps and reform offers.
The European Union is considering banning the import of oil from Syria in an effort to increase pressure on the Assad regime.