Five persons were killed and 18 injured when an under construction staff quarters of the Central University collapsed here on Sunday, police said.
The toll could increase as several of the injured were in a serious condition, they said.
Police and fire service personnel were searching whether more persons were trapped in the debris. A team of doctors had been rushed to the spot to give treatment and first aid, police said.
Some of the seriously injured have been rushed to Thanjavur government hospital.
Police said the roof of the building collapsed while the centering work for concrete slab was in progress, as there was no sufficient support to withstand the weight.
There were also complaints about the quality of construction work and the materials used, police said.
The deceased were identified as Shamir, Kittu, both from Orissa and Mani and Krishnasamy, local construction workers.
Police said they have yet to identify the fifth person.
The injured have been admitted to Government Hospital at Tiruvarur and Thanjavur Medical college hospital.
The Rs 250 crore Central University was coming up on 100 acres of land.