Khokon, a fourth-year student of philosophy and resident of the hall, was severely injured, as the rival JCD activists swooped on him early Wednesday.

Doctors Wednesday night told The Daily Star that Khokon was kept alive by an artificial respiratory system.

"He's suffering from brain haemorrhage. We can't specify his condition before 72 hours," said a duty doctor.

Rashidul Islam Sagar, a fourth-year student of Bangla and the other critically hurt student, suffered multiple wounds all over his body in the attack. He is now receiving treatment at Dhaka Medical College Hospital (DMCH).

Dhaka University (DU) authorities have formed a five-member probe body headed by DU Treasurer Prof Syed Rashidul Hasan and asked it to submit a report within a week.

Vice-chancellor Prof SMA Faiz Wednesday night told The Daily Star at the CMH that the attackers will be given exemplary punishment.

JCD President Sahabuddin Laltu and General Secretary Azizul Bari Helal have meanwhile expelled 10 JCD men in this connection. Sources said Laltu and Helal have asked the expelled activists to leave the hall. Otherwise, they will be handed over to police.

The sources said the expelled still remain on the campus under cover of a top JCD leader.