BAGHDAD/ BEIRUT - Nine fighters from a militia battling Islamic State were killed in northern Iraq when an Iraqi army aircraft fired at them in error, security and militia sources said on Sunday.

The fighters were responding to an Islamic State attack west of Camp Speicher, a former US base outside the city of Tikrit, said Ahmed al-Assadi, spokesman for the Hashid Shaabi, a coalition of mostly militias fighting the militants alongside Iraq's military. More than a dozen fighters were wounded, he said.

Colonel Mohammed al-Assadi, spokesman for the joint police and military operations command in Salahuddin province, said that at 10:30 pm (1930 GMT) on Saturday, an Iraqi army aviation drone opened fire due to mistaken coordinates. Assadi said the drone was being fired at from the ground and "fired on the advancing Jund al-Imam forces, killing nine and wounding around 15," he added, referring to the militia.

Spokesmen for Iraq's defence ministry and joint operations command were not immediately available for comment.

Meanwhile, Syria's Al-Qaeda affiliate abducted two of the country's most prominent media activists from a radio station in the northwestern Idlib province on Sunday, opposition officials 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. According to a statement published by Fresh FM, Al-Nusra fighters stormed the radio station and confiscated its broadcasting and technical equipment as well as its electricity generators.

"The Al-Nusra members then gathered all of the revolution flags and burned them in front of everyone," the statement said.

The flag featuring three red stars over a green, white and black tricolour, in use before President Bashar al-Assad's father and predecessor came to power, is the symbol of Syria's uprising.

Al-Nusra fighters then arrested both Fares and Abdallah, the statement said.

Fares is widely known as the creator behind the often humourous protest posters of Kafranbel, written in English and Arabic and widely circulated online.

"Raed is the founder of Fresh FM, and he's an amazing person," said activist Ibrahim al-Idlibi.

"He did not take up arms at all, not even for personal use... he always came up with new ideas, always strived to be better," Idlibi told AFP via the Internet.

According to Fresh FM employee Ahmad Buyush, Fares, 41, was a medical student when popular anti-regime protests began across Syria in March 2011. "Raed is the revolution, in all meanings of the word," he told AFP. He had been arrested by Al-Nusra in the past and had survived an assassination attempt two years ago, Buyush said.

Founded in 2013, Fresh FM employs more than 80 people and runs medical treatment programmes as well as a blood bank, he said. It broadcasts "national, revolutionary, and religious songs" and programmes on news and social issues.

Al-Nusra did not specify why they arrested Fares and Abdallah, but Buyush suspects it could be a show of force in Kafranbel, which has been in rebel hands since 2012. "I see that the reason is to sabotage and terrorise. They've begun to take control and impose their word, and they began with us," Buyush said.

He said Al-Nusra Twitter accounts later said the arrest had taken place "because Fresh FM broadcasts wickedness and immorality."

Fresh FM's offices have regularly been targeted by jihadists, including a car bomb explosion last summer and a hand grenade attack shortly thereafter.

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.