LAHORE, Pakistan — Lawyers described yesterday how they were beaten by Pakistan’s security forces in the most violent scenes witnessed since a state of emergency was declared last week.

Riot police advanced on a group of barristers and judges three hours after the start of a peaceful protest near Lahore’s High Court.

Demonstrators retreated to the court’s library as they sought to escape the police. But they were then forced out by tear gas and beaten with canes as they attempted to leave the building. Abdullah Khan Dogar, the barrister who led legal arguments against President Musharraf’s decision to seek another term of office last month, said, “This is shameful. It is persecution of the courtroom by a dictatorship.”

Meanwhile, Iftikhar Muhammad Chaudhry, the deposed chief justice, called on his colleagues to maintain protests, saying, “Go to every corner of Pakistan and give the message that this is the time to sacrifice.”

So far, at least 1,500 people, mostly opposition activists and lawyers, have been detained indefinitely. Imran Khan, the cricketer turned politician, has been in hiding since Sunday. In an e-mail to his ex-wife, Jemima, he said yesterday he feared he would suffer retribution.