Government forces have bombed towns and clashed with opposition fighters in several areas of Syria, as thousands of people took part in demonstrations dubbed "Damascus, Here We Come", monitors and activists said.
A Britain-based activist organisation said crowds in all the main centres of year-long revolt across the country on Friday numbered in the hundreds of thousands.
In the capital itself, five people were wounded in Kfar Sousa district as security forces opened fire to disperse protesters, said the Syrian Observatory for Human Rights from London.
Mortar fire crashed into the Bab Dreib and Safsafa et Warsheh districts of Homs city, in central Syria, killing five people, it said.
Security forces opened fire at demonstrators in Hama province, also in central Syria, where army deserters killed a soldier, the monitoring group said, without giving an immediate toll for the protesters.
The organisation said at least three soldiers and a rebel were killed in Aazaz, near the Turkish border.
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"Troops are bombing and helicopters flying overhead. Fighting has been going on since midday [Thursday] between regime forces and [army] deserters in Aazaz," opposition activist Mohammed Halabi in Aleppo province told the AFP news agency.
The city of Aazaz is strategically positioned on the road to safety in neighbouring Turkey for wounded and fleeing civilians as well as being a supply route for Free Syrian Army fighters.
In Maaret al-Numan and other towns of Idlib province, also on the border with Turkey, demonstrators gathered after Muslim weekly prayers in mosques, calling for the trial of regime leaders, said the Observatory.
Large demonstrations were reported in the northern city and region of Aleppo as well as in the Kurdish city of Qamishli on the border with Turkey.
The state news agency SNAA reported that "several terrorists" were killed in the Sermin region of Idlib and in the Aleppo region an army engineer was killed by a bomb under a bridge that was detonated by remote control.
In videos posted online by activists, protests were also seen in the southern province of Daraa, birthplace of the revolt in Syria that monitors say has cost more than 9,100 lives.
Opposition activists said hundreds of people took part in night-time protests in areas of the capital.
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Demonstrators in the Rukneddin neighbourhood chanted "Bomb us instead of Daraa, Homs and Hama", in reference to cities where hundreds of civilians have reportedly been killed in a crackdown on protests.
The reports could not be confirmed because of restrictions on the movements of foreign media.
As the fighting continued, the European Union added Asma al-Assad, the wife of Syrian President Bashar al-Assad, as well as other family members, to the list of individuals targeted by sanctions and travel bans.
Diplomatic efforts to halt the violence will see Kofi Annan, the joint UN-Arab League envoy on Syria, travel to Russia on Saturday for talks with President Dmitry Medvedev and Sergei Lavrov, the foreign minister.
Moscow has been a crucial supporter of Damascus, by vetoing UN Security Council resolutions condemning the government's crackdown. It says both sides are responsible for the violence.
In Geneva, the U.N. Human Rights Council on Friday extended the mandate of a U.N. expert panel tasked with reporting on alleged abuses in the country.
A resolution passed by the 47-member body condemned "widespread, systematic and gross violations of human rights and fundamental freedoms perpetrated" by Syrian authorities, including summary executions, torture and sexual abuse of detainees and children.