Medical sources in the Vakarai hospital inside territory held by the Liberation Tigers of Tamil Ealam (LTTE) said 27 dead bodies of civilians were brought there.
"We also have 65 people wounded who have been brought for treatment," a medical source said by telephone.
He said some areas were still unreachable due to fears of shelling, although there were fewer attacks Monday.
About 25 of the more seriously wounded were evacuated to a better-equipped hospital inside the government-held Batticaloa town with the help of the Red Cross, officials said.
The defence ministry said it had launched a ground offensive on Sunday to neutralise rebel long range weapons, and did not fire multi-barrel rockets, artillery or mortar bombs to protect civilians.
During Sunday's ground offensive "24 security forces personnel sacrificed their lives in this process while another 69 sustained injuries due to ground obstacles," the ministry said.
The LTTE said at least 41 civilians were killed and many m