Activists say the Syrian opposition has taken control of a strategic northern town that is crucial to the government's fierce campaign against rebels in the embattled city of Aleppo.

The Syrian Observatory for Human Rights said Friday forces loyal to President Bashar al-Assad have completely withdrawn from Saraqeb , where the main highways from Aleppo to Damascus and the Mediterranean coast meet.

The Britain-based monitoring group says rebel forces now control an area extending 25 kilometers in all directions from the town. It says government convoys resupplying troops in Aleppo will now likely be more vulnerable to rebel attacks.

Activists say at least 28 soldiers were killed in the attacks on government checkpoints in the area Thursday. Video circulating on the Internet suggested that many of the soldiers were killed execution-style. The video could not be independently authenticated but it drew protests from international rights groups.

There was no immediate response from the Syrian government or from state-controlled media.

Government troops have for months been fighting rebel forces for control of Aleppo, Syria's second largest city.

The Syrian conflict is entering its 20th month and has caused the deaths of an estimated 36,000 people. Hundreds of people were killed in the past week as the government has stepped up airstrikes against rebel-controlled areas.