The state-run Syrian Arab News Agency said the attorney general of the province of Idlib, a judge and a driver were killed by gunfire in their car on their way to work.
A news release from the government of President Bashar al-Assad called the killings an act of an "armed terrorist group," CNN reported.
But the Syrian Network for Human Rights blamed Assad's security forces for the assassinations.
"It is with great regret that we report the regime's security forces have assassinated the Honorable Judge Muhammad Ziyadah and Barrister Nidal Ghazi," the human-rights organization said in a release. "They were deliberately targeted in Idlib with live fire on their very well-known vehicle when they were riding together in one vehicle, by the regime's forces.
"We hold the Syrian regime fully responsible for their assassination and the Syrian Network for Human Rights demands that a case file be opened in the International Criminal Court to investigate this incident and prosecute all those responsible."
For more than 11 months, Syrian civilians have mounted anti-government demonstrations throughout the country and have been met with military force.
The Local Coordination Committees of Syria, a network of opposition activists, says at least 8,500 people have been killed in the political uprising that began in March 2011. U.N. observers' fatality estimates are lower at 5,000.
Meanwhile, China's state-run Xinhua news agency published an unusually political defense of the country's alliance with Assad's government.
"The West … appears to be driven less by their self-proclaimed 'lofty goal' of liberalizing the Syrian people than by geopolitical considerations," the agency wrote.
Earlier this month, China and Russia vetoed a U.N. Security Council resolution condemning Syria's armed response to what has become a civil war.