Police and plainclothes personnel from intelligence agencies launched the crackdown late last night after the lawyers' movement and the main opposition PML-N said they were determined to go ahead with a "long march" to the federal capital on March 12.

Cricketer-turned-politician Imran Khan has gone into hiding after security personnel raided his house in Islamabad as part of the crackdown.

Sources in Khan's party Tehrik-e-Insaf said he had gone underground following raid on his house on Tuesday night.

They said Khan is fully determined to be part of long protest march by the lawyers on March 12.

The organisers of the protest have said it will culminate with a sit-in near parliament on March 16 but interior ministry chief Rehman Malik has warned them to stay away from Islamabad, saying the government will take firm steps to prevent any breakdown of the law and order situation.

The Jamaat-e-Islami said 25 of its activists were arrested at Raiwind in Lahore while Imran Khan's Tehrik-e-Insaf party said 12 activists were detained in the eastern city.

Media reports said security personnel picked up hundreds of lawyers, rights activists and workers of different opposition parties from across the politically crucial Punjab province, which is currently under Governor’s Rule.

There was no official word on the arrests.

The administration in Punjab also imposed prohibitory orders under Section 144 of the Pakistan Penal Code, banning protests and gatherings. Officials said rallies and protests had been banned across the province and the army would be called in to maintain order if necessary.

Leading rights activist Tahirah Abdullah told reporters she was arrested on Tuesday night by security personnel who broke down the door of her house in Islamabad.

She said she was held under the Maintenance of Public Order ordinance, which allows authorities to detain a person without charges for 90 days.

Abdullah, who was released this morning, said the officials who detained her did not have a warrant or any other official document.

Qahsan Iqbal, a dissident leader of the ruling Pakistan People’s Party and a key player in the lawyers’ movement, went into hiding before plainclothes personnel raided his home.

Speaking to a TV channel, he said the government’s actions could not crush the lawyers' movement. The lawyers, he said, were determined to go ahead with the long march.

Athar Minallah, another prominent leader of the lawyers' movement, said the homes and offices of hundreds of lawyers had been raided since Tuesday night.

He said it was unfortunate the government had launched a crackdown though the lawyers had always struggled in a peaceful manner and never resorted to violence despite facing many atrocities.

The PML-N threw its weight behind the lawyers' movement after the Supreme Court last month barred top party leaders Nawaz and Shahbaz Sharif from contesting polls and hold elected office. President Asif Ali Zardari imposed Governor's Rule in Punjab following the apex court's verdict.

Former premier Nawaz Sharif has urged the people to rise in a rebellion against the government. Interior ministry chief Malik said his comments amounted to sedition and could be punished with life imprisonment.

Former Punjab Chief Minister Shahbaz Sharif has vowed to defy the government’s restrictions and join the long march.