Rights activists say Syrian army defectors killed seven government security force members while ambushing a patrol following an army raid that cost 11 civilian lives earlier Tuesday.

The London-based Syrian Observatory for Human Rights says both incidents took place in Idlib province, a restive area that borders Turkey. The observatory and other groups report that security forces and pro-government “shabiha” militiamen swept through villages and attacked infiltrators at the border, wounding dozens.

The Associated Press, quoting activists, reports a senior Syrian officer was killed in a retaliatory ambush by anti-regime fighters. Syrian state-run media also reported that border guards clashed with a group of 15 “terrorists” attempting to enter the country from Turkey, killing two of them.

About 7,500 Syrians have fled across the Turkish border to escape the brutal government crackdown. Military defectors from the Free Syrian Army have found shelter among the refugees and often launch cross-border raids into Syria.

Up to eight more civilians were killed Tuesday in a separate incident in Idlib when Syrian troops fired on crowds attending funeral processions for those killed earlier.

On Monday, United Nations human rights chief Navi Pillay said her office has received credible reports from a variety of sources indicating the Syrian death toll since unrest began in March exceeds 5,000 – a figure rejected by the Syrian U.N. ambassador as “incredible.”

Pillay said the figure includes civilians, defectors and “those executed for refusing to shoot civilians.” It does not include the hundreds of security and military forces the U.N. says are also thought to have been killed.

The U.S. deputy permanent representative to the U.N. Security Council, Rosemary DiCarlo, said the human rights crisis in Syria is a threat to international peace and security. She said the U.N.'s estimate of the death toll in Syria has more than doubled in the past four months, and that it is “unconscionable” that the Security Council has not spoken out about the situation recently.

In October, China and Russia vetoed a draft resolution condemning the bloody crackdown on anti-government protesters. Russian Foreign Minister Sergei Lavrov said Tuesday it is “immoral” for Western nations to accuse Moscow of blocking the Security Council's work, while at the same time refusing to pressure what he called the “armed extremist” parts of the Syrian opposition.

The U.N.'s Pillay said Monday that the state-sponsored violence in Syria should be examined by the International Criminal Court.

Syria's uprising has turned increasingly violent in recent months, with defecting soldiers fighting back against the army and once-peaceful protesters taking up arms to protect themselves.

A general strike continued for a third day Tuesday in several regions across Syria as activists push for an end to Mr. Assad's rule through a campaign of civil disobedience.