The United Nations has expressed concerns about civilian deaths in the Wanni, saying dozens had been killed.

Resident coordinator Neil Buhne told the Associated Press news agency the situation was desperate.

"There have been many civilians killed over the last two days. It´s really a crisis now."

He said both sides had been trying to reduce civilian casualties but added: "In the current phase, with such a level of fighting and with so many people around, unless there is very, very close attention to it, it´s almost inevitable."

Buhne said there had "definitely been fighting" in the safe zone.