Two of Syria’s most prominent activists have been arrested by a powerful al-Qaeda affiliate after a raid on their opposition radio station.

Jabhat al-Nusra, a hardline rebel faction, ransacked Radio Fresh and seized its manager Raed Fares and his colleague Hadi al-Abdullah.

The two men live and work in Kafr Nabl, a town in Idlib province that is famous for satirical English-language banners used to draw attention to the Syrian conflict.

According to a statement by the Kafr Nabl media centre, Mr Fares and Mr Abdullah were arrested at 8am on Sunday when members of al-Nusra raided the station.

It forced staff to step on the green, white and black flag of the original Syrian revolution – since rejected by the group in favour of a black banner – before burning it.

When they asked why they were being punished, the Islamists are said to have replied: “We don’t want media.” They confiscated all the computers, cameras and broadcasting equipment before daubing on the walls: “Seized by Jabhat al-Nusra. No entry.” Al-Nusra supporters claimed on social media that the pair had been arrested because the station broadcast music and other “wickedness and immorality”.

Ahmad al-Bayoush, the station’s executive manager, confirmed that they had received warnings about playing music. “They said that the songs were inciting evil and immorality,” he told The Independent.

“That is unacceptable to us,” he said, adding that the station only broadcast “revolutionary songs”.

Mr Fares, 41, had previously been detained by al-Nusra, which disapproved of what it termed the station’s “secular tendency and support of apostates”.

Ibrahim al-Idlibi, an activist in Idlib, told AFP that Mr Fares was “an amazing person”. He said: ”He did not take up arms at all, not even for personal use... he always came up with new ideas, always strove to be better.”

His colleague, Mr Abdullah is a citizen journalist whose reports on YouTube have been viewed tens of thousands of times.

Last month, he was one of four journalists to be granted a rare interview with al-Nusra’s leader, Abu Mohammad al-Golani.

Despite accusations that he was too close to the Islamists, he challenged Mr Golani over the fairness of its judicial system – an encounter that some suggested may have prompted his arrest.

Despite its hardline sectarian views and rejection of democracy, al-Nusra has sought to learn from al-Qaeda’s previous mistakes by embedding itself in communities. As well as providing social services and limiting food prices, it has been careful not immediately to impose harsh interpretations of sharia law for fear of alienating locals.

Mr Bayoush said that he believed that the arrests were a sign that the group was showing its true face. “They’ve begun to take control and impose their word, and they began with us,” he said.

Designated a terrorist group by the US and Britain, al-Nusra has been excluded from the Syrian peace talks due to begin later this month. Other hardline Islamist groups, such as Ahrar ash-Sham, have been invited.

In a sign of the obstacles ahead, the Syrian government announced over the weekend that it was ready to attend talks in Geneva but only if what it termed “terrorist” groups were excluded.

Analysts have warned that no ceasefire will hold unless it has the agreement of armed factions, including those considered hardline. But the Syrian President, Bashar al-Assad, has branded all those battling against his government as “terrorists”.

In a separate development, the International Committee of the Red Cross said it hoped that an aid convoy would reach the besieged town of Madaya on Monday, where starving residents have been forced to eat weeds, cats and dogs.