Sri Lankan health officials say at least 30 people were killed Thursday when the military shelled a village and a makeshift hospital in the country's north.
The officials say the shelling occurred within a government-declared safe zone. They say shelling in the area has killed a total of at least 66 civilians since Tuesday.
The military has denied firing into the safe zone.
Sri Lanka's Tamil Tiger rebels also faced allegations of wrongdoing Thursday, with the United Nations saying the rebels are blocking U.N. staff and their families from leaving rebel-controlled areas in the north.
Sri Lanka's military has advanced into the rebels' strongholds in recent weeks. Thrusday the military said it captured a building in the Mullaittivu district that appeared to be the Tigers' main operations center.
The military has moved further into rebel territory after a series of victories, including the capture of the rebels' de-facto capital, Kilinochchi, and the seizure of the strategic Elephant Pass.
Journalists are barred from the war zone, making it difficult to confirm reports from the two sides of the conflict.
Tamil Tiger rebels have been fighting since 1983 to establish an independent homeland for Sri Lanka's ethnic minority Tamils, who they say face second-class treatment by the Sinhalese majority. More than 70,000 people have died in the conflict.
Some information for this report was provided by AFP, AP and Reuters.