Beirut: Syria has entered a state of civil war with more than 4,000 people dead and an increasing number of soldiers defecting from the army to take up arms against President Bashar Assad's regime, the UN's top human rights official said on Friday.

Syrian President Bashar Assad has been trying to crush an 8-month-old revolt against his autocratic rule, but the violence has only intensified.

The UN High Commissioner for Human Rights, Navi Pillay, said the UN is putting the death toll for the revolt "at 4,000 but really the information coming to us is that it's much more than that."

"As soon as there were more and more defectors threatening to take up arms, I said this in August before the Security Council, that there's going to be a civil war," Pillay told reporters in Geneva. "And at the moment that's how I am characterizing this."

The scathing criticism from Pillay comes as the pressure piles on Assad from home and abroad. On Friday, the European Union imposed fresh sanctions on Damascus, and the Syrian opposition called a general strike inside the country.

The recent spate of economic sanctions from the EU, the Arab League and Turkey are punishing Syria's ailing economy, a dangerous development for the government in Damascus.

Syrian business leaders have long traded political freedoms for economic privileges in the country, where the prosperous merchant classes are key to propping up the regime. But the sanctions, coupled with increasing calls for strikes, could sap their resolve.

The new EU sanctions target 12 people and 11 companies, and add to a long list of those previously sanctioned by the EU. The full list of names of those targeted will not be known until they are published in the official journal of the EU on Saturday.