Tunisian Femen activist Amina Tyler has been arrested in the city of Kairouan, 150km south of Tunis, after staging a protest outside a mosque during violent clashes between police and hardline Islamists.
Police took the member of radical feminist movement into custody after she spraypainted the Femen name on a wall outside the Great Mosque of Kairouan, also known as Oqba ibn Nafa mosque.
"Amina continued the anti-Islamist campaign of Femen for freedom for women in the very heart of the sharia stronghold," Femen said.
A video posted online by Femen depicts Amina talking to police and passersby outside the mosque before being taken away in a police van.
According to some media reports, police arrested her to protect her from an angry mob.
Amina received death threats and sparked controversy across the Muslim world for posting topless pictures of herself online with the words 'F**k your morals' emblazoned across her chest earlier this year.
Kairouan - Tunisia's main religious centre - was swamped with security forces as authorities blocked an annual conference of the ultra-conservative Muslim group Ansar al-Shariah.
Clashes erupted and protesters threw stones at police who responded with teargas. Five civilians and four policemen were injured, according to a spokesman for Kairouan hospital.
The group moved on to the northern Tunis suburb of Ettadamon where they were confronted by police teargas and warning shots.
A 27-year-old protester was killed and 11 policemen injured.
Prime Minister Ali Larayedh, of the moderate Islamist Ennahda Party, said 200 Ansar al-Shariah members were arrested across the country, Arabic daily al-Hayat reported.
"This group is engaged in violence, is opposed to the state and revolts," the PM said.
The Tunisian government had been previously criticised for taking a soft stance against Ansar al-Shariah, whose leader, Seifallah Ben Hassine, is wanted for his involvement in a mob attack on the US embassy in September.
The group has become increasingly aggressive and has been accused of attacking art galleries, police stations and cinemas since the Arab Spring uprising that overthrew former president Ben Ali.