LAHORE, Pakistan, Nov. 14. The opposition politician Imran Khan emerged from hiding today to the cheers of hundreds of students at a protest demonstration against Pakistan’s president, Gen. Pervez Musharraf, at a university here and was quickly seized by hard-line students and turned over to the police, witnesses said.

In another development, Benazir Bhutto has started to rally opposition parties into a coordinated movement against General Musharraf, her party spokeswoman, Sherry Rehman, said in an interview today.

Ms. Bhutto, a former prime minister who has been placed under house arrest in Lahore, has contacted the main opposition parties and has received a favorable response, Ms. Rehman said. She wants a one-point agenda for the restoration of democracy, Ms. Rehman said.

Ms. Bhutto’ s move to bring opposition parties into a united front against General Musharraf is likely to increase the pressure on the military leader and strengthen calls for an end to emergency rule, under which the constitution has been suspended and thousands of people placed under detention or house arrest.

This is a logical reaction to the events of the last week and the brutal behavior of the state, Ms. Rehman said. They have locked up not only her, but thousands of party workers. The whole central leadership is under house arrest.

[A senior police official told The Associated Press today that Ms. Bhutto will remain under house arrest in Lahore for at least another day. “The position for her will remain like this until at least tomorrow. Then the government will review what to do with her,’’ the official said on condition of anonymity, because the matter was politically sensitive and no decision had been taken to release her.]

Ms. Bhutto, who returned to Pakistan last month to contest elections under an agreement with General Musharraf, has hardened her stance since he imposed the emergency. On Tuesday she called for General Musharraf to resign from both his posts of chief of army staff and president and restore the country to democratic rule, and demanded that the international community stop backing the general.

Among the parties she has approached are that of former prime minister Nawaz Sharif, who is in exile in Saudi Arabia, and Mr. Khan’s Movement for Justice party.
Ms. Bhutto has also been in touch with the religious parties opposed to General Musharraf, Ms. Rehman said.

Mr. Khan, the cricketer-turned-politician and a vociferous opponent of General Musharraf, was seized today by hard-line students angered at his presence on a university campus in Lahore and handed over to police, witnesses said. He was the only major opposition political figure not placed under detention since General Musharraf imposed emergency rule in Pakistan on Nov. 3.

Mr. Khan’s appearance at Punjab University, one of the country’s oldest universities, was coupled with high drama. Hundreds of students waited for him in front of Faisal Auditorium, chanting slogans like Go Musharraf, Go and No to Emergency!

Muhammad Asim, 25, a student of administrative sciences, said he was protesting against the suspension of fundamental human rights in Pakistan. He was holding a placard that read. Our hearts are crying with indignation.

Students affiliated with the radical Islamic party Jamaat-e-Islami were also at the rally, chanting slogans against President George W. Bush and the United States.

Mr. Khan, a style icon and symbol of defiance for youth here, was expected to make a speech to the students to rally them against Musharraf, said Saloni Bokhari, the president of the women’s wing of Mr. Khan’s political party

At around noon, to the delight of his student supporters, Mr. Khan suddenly appeared. Several students hoisted the opposition leader triumphantly into the air. Mr. Khan, visibly pleased by the reception, was making a victory sign when he was seized by students belonging to Islami Jamiat-e-Talba, the student wing of Jamaat-e-Islami.

The students hustled Khan into a nearby building and detained him there for about an hour.

We have taken him inside to prevent him from arrest and to make sure he joins the protest in an organized manner,’’ said one of the Islami Jamiat-e-Talba students.

Mr. Khan was then put in a white van and driven off campus, where police arrested him. As the van moved through the melee, students smashed its windows.

A senior police official, Aftab Cheema, told the Associated Press that Mr. Khan is being held at an undisclosed location, and will be charged with crimes yet to be determined.