The police here on Saturday detained around 40 students and teachers protesting at the Delhi University's Arts Faculty without permission to press for the release of former professor G N Saibaba, officials said, hours after the Supreme Court stayed his acquittal by the Bombay High Court in a Maoist-links case.

The Left-backed All India Students' Association, however, claimed the number of detainees is higher, and also alleged the protesting students and teachers AISA members were "beaten up and manhandled" by the police.

The protest was organised after the Supreme Court suspended a Bombay High Court order acquitting Saibaba and others in a Maoist-links case.

"Students and professors who were peacefully protesting against the stay on the acquittal and wrongful incarceration of our professor, G N Saibaba were brutally detained, beaten up and manhandled," AISA National Working General Secretary Prasenjeet.

"Around 60 people were detained. The protestors were taken to two police stations. Some of the students were taken to the Maurice Nagar Police Station and the rest were taken to Burari Police Station," he added.

The police said the students were told they were not given a permission by the university administration to hold a protest on the campus, but they insisted and "misbehaved with the police and security staff of the university".

"On Saturday around 2.30 pm, some students having affiliation with AISA and other Left organisations started gathering outside the Arts Faculty, Delhi University North Campus. Initially some five students came and started raising slogans," Deputy Commissioner of Police (north) Sagar Singh Kalsi said.

"They were explained about the denial of permission to hold protest and were directed to disperse, but instead of dispersing they started calling their other friends for protest and their number rose to around 40," Kalsi added.

The action was taken after the university authorities gave in writing to take legal action as protesting students were disturbing the peace, police added.

"During the process of removal, they resisted and misbehaved with the police and security staff of the university. Now the situation is peaceful," the police said.

The Nagpur bench of the Bombay High Court had on Friday acquitted Saibaba and ordered his release from jail, noting that the sanction order issued to prosecute the accused in the case under the stringent provisions of the Unlawful Activities (Prevention) Act was "bad in law and invalid".

The high court had also allowed the appeals filed by five other convicts, acquitting them of all charges. The prosecution had moved the apex court against the acquittal.

Saibaba, 52, is lodged at the Nagpur Central Jail.