The UN Human Rights Council (HRC) has launched a new commission of inquiry into Syria's crackdown on anti-government protesters, including possible crimes against humanity.
The announcement came as rights activists on Tuesday claimed that 18 more people have been killed in the country over the past 24 hours, including seven in the city of Homs.
By 33 votes in favour to four against and nine abstentions, the HRC passed a resolution to "urgently dispatch an independent international commission of inquiry... to investigate violations of international human rights law in Syria since July 2011".
"The resolution is adopted," Uruguay's ambassador Laura Dupuy Lasserre who chairs the council, announced after the vote.
The remaining countries on the 47-nation council abstained or were absent. China and Russia said they opposed the measure as unnecessary intervention.
Fayssal al-Hamwi, the Syrian Ambassador, called the action "100 per cent political".
Meanwhile, the security crackdown continued in key areas across the country, Al Jazeera's Nisreen el-Shamayleh said, reporting from Ramtha on the Jordan-Syria border on Tuesday.
"We undersand that at least 55 tanks are currently raiding the town of al-Khowria in Deir ez-Zor. These tanks are shelling some of the neighbourhoods there," Shamayleh said.
"We also heard that some of the soldiers reportedly descended from two helicopters down to al-Khowria in that neighbourhood. An attack is ongoing there.
"We have also understood that the troops are destroying the homes and burning them and many arrests were made and the residents protested the attacks by taking to the streets."
Meanwhile, Robert Ford, the US ambassador to Syria, made a surprise visit to Jassem, an area in the southern Deraa province which has seen some of the worst violence.
Ford angered Damascus seven weeks ago when he paid a visit to Hama in a gesture of solidarity with the city where huge anti-Assad protests occurred in June and July.
Over 2,200 dead
President Bashar al-Assad has tried in vain to crush the five-month-old revolt, blaming it on Islamic extremists and thugs.
"Leaders should know that they will be able to remain in power as long as they remain sensitive to the demands of the people," Ahmet Davutoglu, the Turkish foreign minister, said on Monday.
Turkey, a former close ally of Syria and an important trade partner, has grown increasingly frustrated with Damascus over its deadly crackdown.
The violence has left Syria facing the most serious international isolation in decades, with widespread calls for Assad to step down.
Human rights groups say more than 2,200 people, most of them unarmed protesters, have been killed in the government's crackdown on the uprising.
In an interview broadcast on state TV on Sunday, Assad warned against foreign military intervention in his country, saying: "Any action against Syria will have greater consequences [on those who carry it out], greater than they can tolerate".
Assad also spoke about political reforms, saying local elections were to be held within months, to be followed by parliamentary polls in February 2012.
On Monday, he signed a decree setting up a commission - chaired by the prime minister and comprising a magistrate and two lawyers - tasked with legalising political parties.