Syrian forces bombed towns and clashed with rebels in several regions on Friday as activists said thousands staged anti-regime protests and the European Union slapped sanctions on the country's First Lady.
In Geneva, the UN Human Rights Council ordered the extension of a probe into violations in Syria, and asked investigators to map out abuses since a deadly crackdown on protests in the country erupted in March 2011.
UN-Arab League envoy Kofi Annan was to travel this weekend to Moscow and Beijing, which have blocked Security Council action against Syria over the crackdown, but he had no immediate plans to return to Damascus.
Diplomats in Brussels said EU foreign ministers had agreed an assets freeze and travel ban on "Assad's wife, mother, sister and sister-in-law," and eight other entourage members.
Asma Assad, whose parents live in Britain where she grew up, cannot be barred entry to the country but is not expected "to try to travel to the United Kingdom at the moment," British Foreign Secretary William Hague said.
Washington hailed the EU move and said it was looking into what more can be done.
"We are gratified that the EU has taken yet another step in tightening the noose on the Assad regime," US State Department spokeswoman Victoria Nuland said.
The president himself was targeted last May 10, along with his younger brother Maher and four cousins.
Demonstrators in all the hot spots of anti-regime revolt across Syria on Friday numbered hundreds of thousands, the Syrian Observatory for Human Rights said.
While they protested under the slogan of "Damascus, here we come," eight people were wounded in the Kfar Sousa district of the capital as security forces opened fire to disperse protesters, it said.
At least 33 people were killed in violence nationwide on Friday, the Britain-based group said -- 17 civilians, 13 soldiers and three army deserters.
Nine civilians died in Homs districts hit by gunfire and rockets, it reported.
Fighting raged in the town of Aazaz in the northern province of Aleppo near the Turkish border, the Observatory and activists said. At least three deserters and a civilians were reported killed.
"Troops are bombing and helicopters flying overhead. Fighting has been going on since midday (Thursday) between regime forces and (army) deserters in Aazaz," activist Mohammed Halabi told AFP in Beirut by telephone from the province.
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Aazaz is strategically positioned on the road to neighbouring Turkey, as well as being a supply route for Free Syrian Army rebels. The fighting has send refugees across the border to Turkey.
Fierce clashes also erupted in mid-afternoon between soldiers and deserters in the villages of Haritan and Anadan, between Aleppo and Aazaz, Halabi said. The Observatory said two civilians were killed in Anadan.
Deserters attacked a convoy of tanks headed for Aazaz, prompting the troops to shell the two villages, the activist said.
Large demonstrations were reported in Aleppo and in the Kurdish city of Qamishli on the border with Turkey.
The state news agency SNAA reported "several terrorists" killed in the Sermin region of Idlib and said that in the Aleppo region an army engineer was killed by a bomb under a bridge.
In videos posted online by activists, protests were seen in the southern province of Daraa, birthplace of the revolt that monitors say has cost more than 9,100 lives.
UN human rights expert Yakin Erturk, meanwhile, told a news conference on Friday that at least four Syrian brigadier generals have defected in recent weeks, indicating "that high levels of defections are increasing" in Syria.
In diplomatic efforts to halt the bloodshed, the Security Council on Wednesday adopted a statement urging Assad and his foes to implement "fully and immediately" Annan's peace plan.
The initiative calls for Assad to pull troops and heavy weapons out of protest hubs, a daily two-hour humanitarian ceasefire, access to all areas affected by the fighting and a UN-supervised halt to all clashes.
Annan's spokesman said a team of technical experts had returned to Geneva after "three days of intensive talks with Syrian authorities on urgent steps to implement" the plan.
On Friday, Russian President Dmitry Medvedev warned against any attempt to circumvent UN authority.
"There's a need to eliminate any loopholes allowing (nations) to act in circumvention of the authority of the Security Council and use force without its approval," Medvedev told a European security conference in Moscow.
The Security Council still awaited a formal Syrian response on Wednesday's statement, but government daily Tishrin welcomed it.
Riyadh, Doha, Ankara "and other capitals which are enemies of Syria, and which wanted a military intervention... suffered a defeat on the international stage," it said.
The opposition Syrian National Council poured scorn on the UN statement, saying it would give the regime more time to continue killing its own people.