Bahrain has been rounding up pro-democracy activists ahead of its controversial staging of the April 21 Formula One Grand Prix two years after a bloody crackdown, Human Rights Watch said on Wednesday.
Plainclothes police officers have arrested 20 people so far in raids in towns around the Gulf state's Sakhir circuit, the New York-based watchdog said.
"Bahraini authorities are carrying out home raids and arbitrarily detaining opposition protesters in advance of the Formula 1 Grand Prix weekend," it said.
"These raids and detentions suggest that officials are more concerned with getting activists out of circulation for the Formula 1 race than with addressing the legitimate grievances that have led so many Bahrainis to take to the streets," said HRW's Middle East director Sarah Leah Whitson.
"The Bahraini authorities have a responsibility to ensure the safety of those attending the Formula 1 Grand Prix, but that should not extend to arresting people for exercising their legitimate rights to free speech and assembly," Whitson said.
"Night-time raids of targeted people by masked officers who show neither arrest nor search warrants appear intended to intimidate them, their families and their supporters."
Sunni-ruled Bahrain was rocked by month-long pro-democracy protests led by the kingdom's Shiite majority in early 2011 that were crushed with the help of Saudi-led troops.
Last year's Bahrain Grand Prix was accompanied by a week of angry Shiite-led protests but demonstrators stayed away from the desert circuit and the race passed off without incident.
A total of 80 people have been killed in Bahrain since the protests erupted in February 2011, according to the International Federation for Human Rights.