Syrian Free Army guerillas captured dozens of members of President Bashar al-Assad's security forces while seizing two military checkpoints in the Jabal Al Zawiyah region of the northern province of Idlib.
SFA fighters also clashed with security forces at a third checkpoint, killing and wounding an unspecified number of loyalist soldiers.
Rami Abdul Rahman, director of the British-based Observatory, said it was not immediately clear how many people had been killed or captured by the rebels.
The SFA, comprised mostly of armed army defectors, has launched an effective and highly deadly insurgency targeting Assad's forces in recent months, often striking deep into the heart of the country.
Led by dissident Syrian Colonell Riad Assad and his confederates, who have been given safe-haven in Turkey, the ranks of the SFA have swelled to some 20,000 fighters.
The growing SFA insurgency in Syria has combined with the now nine-month long protest movement and intense sanctions from the Arab League and Western nations to destabilize Assad's embattled regime.
Nonetheless, Assad has ratcheted up his bloody crackdown in the past month as desperation has taken root in the halls of power in Damascus - with UN officials saying the number of civilians killed since protests began is rapidly approaching 6,000. Syrian officials say over 2,000 security forces have been killed as well.
Meanwhile in Germany, police say a Syrian man was fatally shot by two people who fired at him as his car stopped at a traffic light.
In a statement, police said the shooting happened late Sunday night in Sarstedt.
The two people are believed to have approached the man's car when it stopped and fired into it several times before fleeing.
Authorities didn't name the victim, but said he was 35 and lived in the nearby city of Hildesheim. There was no word on the possible motive for the killing.