The ambassadors of Italy and the United States and a UN coordinator were among more than a dozen people wounded in a shell attack carried out by Tamil Tiger rebels on Tuesday.

"The government will take immediate measures to enhance security for embassies or international organisations," the ministry said in a statement.

It said diplomats had expressed concern about security following the attack, one of the worst against foreigners in the country's civil war.

Meanwhile, the bodies of five men shot in the head with their hands tied together and blindfolded were found yesterday by Sri Lankan police, who called the deaths an apparent "execution-style killing".

The grisly find in a marsh at Kandana, 15km north of the capital, was made after a child spied one of the bodies in the marsh, a police spokesman said.