A humanitarian assessment team led by the World Health Organization visited Shifa Hospital in northern Gaza on Saturday to assess the situation, the WHO said in a statement.
The team included public health experts, logistics officers and security staff from various United Nations departments.
Due to security risks, the team was able to spend only an hour inside the hospital and described it as a "death zone," WHO said.
Signs of shelling and gunfire were evident. The team saw a mass grave at the entrance of the hospital and was told more than 80 people were buried there, the WHO statement said.