Aamron, a popular Togolese rapper known for criticising President Faure Gnassingbe's rule, reappeared on Thursday in a video apology after more than a week in detention, saying he regretted making "insulting" comments about the head of state.

Aamron, whose real name is Essowe Tchalla, was taken into custody from his home in the capital, Lome, on May 26, hours after he called for a satirical mobilisation on June 6 to mark President Faure Gnassingbe's birthday, his mother said on social media.

The arrest sparked outrage from opposition groups and civil society, who denounced what they called a crackdown on dissent.

Gnassingbe has led Togo since 2005, succeeding his father who ruled for nearly four decades. He recently consolidated power by shifting to a parliamentary system with himself at the helm.

'Sincere apologies'

"I made a series of videos in which I used insulting and outrageous language against the President of the Council, Faure Gnassingbe," Tchalla said in the video, which was widely shared on social media.

"I would like to take this opportunity to ask for forgiveness and express my sincere apologies to His Excellency Faure Gnassingbe."

Tchalla said he had been transferred to a psychiatric centre in Zebe, around 50 kilometres (30 miles) east of Lome, for what was described as "severe depression."

"After a few days of treatment, today I feel more calm and realise the seriousness of my words and my mistakes," he said.

'Arrested for treatment'

According to sources close to the powlice, the artist was arrested to be "treated."

"He was not fully in possession of his faculties," a gendarmerie officer told AFP.

But political figures and Tchalla's relatives dismissed the claim.

"Aamron was arrested because of his activism," said Nathaniel Olympio, a spokesperson for the Don't Touch My Constitution Front, a coalition of opposition parties and civil society groups.

Another activist, Honore Sitsope Sokpor – known online as "Affectio" – has been jailed since January over a poem he published on social media.