Iranian film director Jafar Panahi has been arrested by security forces in his Tehran home, according to reports from an opposition website.
The director, his wife and daughter plus about 15 guests were taken into custody Monday night, and his house was searched.
The Canadian government has expressed "deep concern" over reports of Panahi's arrest and called for his release on Tuesday.
"Canada continues to have deep concerns with Iran's human rights practices. We continue to call on Iran to live up to its human rights obligations in law and practice," the government said in a statement.
Panahi has had frequent run-ins with Iranian authorities over his hard-hitting depictions of its society in films such as Crimson Gold and The Circle, winner of a Golden Lion in Venice.
He also won the Silver Bear and a grand jury prize at the Berlin Film Festival in 2006 for Offside, a film about a group of female soccer fans who sneak in to see a men's match. He was prevented from travelling to the festival this year by Iranian authorities.
Iranian security said a travel ban was imposed on Panahi, who was scheduled to take part in a panel discussion in Berlin last month, after he appeared wearing green, the colour of the opposition, at a Montreal film festival.
Panahi has supported the opposition to hardline President Mahmoud Ahmadinejad, who was re-elected last June.
He was also briefly arrested after attending a memorial to student Neda Agha Soltan, killed at an opposition rally, according to the BBC.
The Tehran prosecutor's office has confirmed his more recent arrest to reporters but denied it was connected to politics or to his art, saying he was arrested on a judge's orders. A computer and other personal effects were seized.
In France, Culture Minister Frederic Mitterrand called on the Iranian authorities to release him. A group of French film directors is also lobbying for his freedom.