Security forces in Pakistan say they have arrested three suspected Islamic militants during a search operation in the country's North West Frontier Province.

Military officials say the operation took place in the militant stronghold of Imam Dheri, in the Swat Valley.

Officials say security forces have established a permanent checkpoint in the area.

Swat Valley was the base of radical cleric Maulana Fazlullah, who has called for a holy war against the Pakistani government. Last year, Pakistani security forces pushed Fazlullah's militants out of territory they had seized in the tourist area.

Meanwhile, Pakistani President Pervez Musharraf called on lawyers who oppose him to stop, in his words, "spreading anarchy" in the country.

He spoke after fighting between his supporters and opponents killed at least 10 people in the southern city of Karachi on Wednesday.

Pakistan's pro-Musharraf opposition boycotted Thursday's parliament session, saying its members were the victims of Wednesday's violence.

Elsewhere Thursday, hundreds of anti-Musharraf lawyers marched in the eastern city of Lahore chanting slogans against the president.

In other news, Pakistani police say at least six people were killed Thursday when a gas cylinder exploded at a scrapyard in Lahore. At least eight other people were injured in the blast.

Some information for this report was provided by AFP, AP and Reuters.