|Pillay's criticisms came as tanks continued to keep towns and villages in a central Syrian region surrounded [EPA]
The United Nations has condemned the "shocking" brutality of Bashar al-Assad's government, with activists saying that at least 15 people have been killed in the latest crackdown on pro-democracy protesters.
Navi Pillay, the UN high commissioner for human rights, criticised on Monday the government's conduct, saying the actions were shocking in their disregard for human rights.
"The brutality and magnitude of measures taken by the governments in Libya and now Syria have been particularly shocking in their outright disregard for basic human rights," she told the UN Human Rights Council in Geneva, Switzerland.
For a second straight day on Monday, dozens of tanks circled towns and villages in the Homs area, north of Damascus.
At least 14 people were shot dead on Sunday and Monday in Rastan and Talbiseh, towns in the flashpoint central region of Homs.
Among those killed was "a little girl called Hajar al-Khatib", the AFP news agency reported.
"Two bodies were found at dawn on Monday in the Baba Amr neighbourhood of Homs", which the security forces had closed off with several roadblocks, an activist, who said he had a list of names, told the AFP anonymously.
For its part, Syria's deputy foreign minister accused Western powers of seeking a return "to the colonial era" in his country by initiating action against his country at the UN, the official SANA news agency reported.
"It is about imposing hegemony on Syria and using the United Nations as a way of re-establishing colonialism and to justify interference," Faisal Meqdad said.
'Culture of violence'
In her remarks, the UN's Pillay said "resort to lethal or excessive force against peaceful demonstrators not only violates fundamental rights, including the right to life, but serves to exacerbate tensions and tends to breed a culture of violence".
She also renewed a call to the Syrian authorities to allow a fact-finding mission to visit the country.
At least 13 people were arrested on Monday in Daraa, a hotbed of the unrest, Rami Abdel Rahman, head of the London-based Syrian Observatory for Human Rights, said.
"The security forces have encircled Mleiha in Daraa province" and carried out arrests, he said, adding that he had the names of 13 detainees.
Also on Monday, police continued to sweep the Homs region as hundreds of people wounded in the crackdown were hospitalised in the nearby city of Hama.
SANA said four soldiers were killed and 14 wounded by "terrorist groups" in Talbiseh on Sunday before a number were arrested and a large quantity of weapons seized.
Activists said protesters took to the streets of Hama and Saraqeb, near Idleb in the northwest, during the night to call for the downfall of Assad's government. Hundreds of people also marched on Sunday in Douma and Jdaidat, on the outskirts of Damascus.
More than 1,000 people have been killed and 10,000 arrested since the revolt began, human-rights groups say. Syrian authorities say 143 soldiers, security forces and police have been killed.
Egypt joined on Monday the chorus of countries urging Assad's government to enact reforms to satisfy pro-democracy protesters.
"We hope that the Syrians in a peaceful manner resolve their problems," Nabil al-Arabi, Cairo's foreign minister, said during a trip to India.
"Whatever reforms the people would like, it should be looked at in a positive manner."