Syria's Al-Qaeda affiliate stormed a radio station and abducted two prominent media activists from a rebel-held northwestern town on Sunday, an opposition official told AFP.

"Al-Nusra Front kidnapped at 0655 (0455 GMT) activists Hadi al-Abdallah and Raed Fares in the offices of Fresh FM where they work and live in Kafranbel," said Soner Taleb, head of media at the Syrian National Coalition.

Fares, Fresh FM's director, has previously been detained by Al-Nusra fighters, who disapprove of what they term the station's "secular tendency and support of apostates", Taleb said.

Abdallah shot to prominence in 2011 when anti-regime protests erupted across Syria, before the country's descent into civil war. Last year he was one of the journalists to interview Al-Nusra's head, Abu Mohammad al-Jolani.

"Abdallah had used his Al-Nusra connections to keep his freedom but this time the jihadists detained them both and destroyed and confiscated their belongings at the station," Taleb said. 

Kafranbel, in northwestern Idlib province, has been under rebel control since 2012 and is well known for its creative and often humourous protest banners, in English and Arabic, which are widely circulated online.

The Syrian Observatory for Human Rights monitor confirmed the abduction of Abdallah and Fares.

Al-Nusra is part of a powerful alliance known as the Army of Conquest that captured Idlib earlier this year, and it has a strong presence in other parts of the country.