Syrian security forces killed Thursday at least 12 people as army defectors attacked army posts amid a Russian warning of a "civil war" in the country, dpa reported.
Omar Idlibi, a Syrian activist based in Lebanon, told dpa that the dead included four deserters outside the city of Hama, an eight-year-old child in the town of Deir al-Zour, and two civilians in the central city of Homs.
He added that the Syrian Free Army, a group of defectors, had attacked three military facilities - two on the outskirts of the capital Damascus and a third near the Syrian-Turkish border.
The defectors' attacks, carried out for the second consecutive day, have raised concerns among Syria's traditional allies, Russia and China.
Russian Foreign Minister Sergei Lavrov compared Thursday the situation in Syria to a "civil war."
Lavrov called on Syrian President Bashar al-Assad to make immediate democratic reforms, and suggested he allow international observers into the country.
"We (Russia) support the idea that observers be deployed there. As far as I know, several days ago, the Syrian leadership said it was ready to accept observers from the Arab League," Lavrov was quoted by the Itar-Tass news service as saying.
"China is highly concerned about the developments in Syria," the Foreign Ministry spokesperson Liu Weimin said on Thursday.
China and Russia vetoed a resolution in the UN Security Council to condemn Syria in October.
Catherine Ashton, the European Union foreign policy chief currently visiting Russia, said it was time for al-Assad to step aside.
"The time has come for Assad to go," Ashton said Thursday in Moscow, according to the Interfax news agency.
The violence in Syria came a day after the Arab League foreign ministers gave Damascus three days to accept Arab monitors and halt its violent crackdown on opposition.
Syria's ambassador to the United States, Imad Mustafa, said Thursday that Damascus was looking into the organization's proposal to send monitors to Syria to protect civilians.
"We will positively address matters that serve Syria's interests," Mustafa told Lebanon-based Al Manar Television.
In Turkey, the head of the opposition Syrian Muslim Brotherhood said the Syrian people would accept Turkish "intervention" in the country to resolve the eight-month unrest, in which more 3,500 people have been killed since March.
"The Syrian people would accept intervention coming from Turkey, rather than from the West, if its goal was to protect the people," Mohammad Riad Shakfa, added on Thursday.
The Turkish pro-government daily Sabah reported Thursday that the opposition Syrian National Council and the Muslim Brotherhood had asked Ankara to establish a no-fly zone over Syrian areas near their shared border to protect civilians.
There was no Turkish official comment on the report.
Turkey has emerged as one of vociferous critics of the Syrian government's crackdown on pro-democracy protesters.