United Nations secretary-general Ban Ki-moon has condemned a Tamil rebel artillery attack in Sri Lanka that injured several foreign diplomats who were on a humanitarian assessment mission.

Mr Ban's spokeswoman, Michele Montas, has told a press briefing he condemns the shelling by the Liberation Tigers of Tamil Eelam (LTTE) in Batticaloa district.

"[It] was in total disregard for the lives of civilians, humanitarian workers, government officials and the international community," she said.

She said a UN resident coordinator was among at least 12 people injured in Tuesday's shelling.

The Sri Lankan Government says the ambassadors of Italy and the United States were also hurt in the raid.

The diplomats were visiting Batticaloa for the first time after security forces last month dismantled a de facto separate state the Tigers ran in the region for over a decade.

The Sri Lankan military retaliated for Tuesday's attack with air attacks against suspected LTTE positions, military officials said.

The LTTE said at least 20 civilians were wounded in the Government's air assault.

Ms Montas says Mr Ban calls on the Government and the LTTE "to end the destructive spiral of violence and ... to make every effort to return to the peace process as soon as possible".

Tuesday's shelling of two military helicopters transporting ambassadors from France, Germany, Italy, Japan, the US and the EU delegation and the heads of three UN agencies was one of the worst ever against foreigners in the country's lengthy civil war.

- AFP