A US weapons team arrived in southern Iraq yesterday to begin probing a cache of mortar shells leaking a substance that early tests indicate could be a harmful chemical agent, a Danish military spokesperson said.

Major Kim Gruenberger said initial tests on the shells by Danish experts who recovered the cache near the southern city of Basra showed they contained a blistering agent similar to substances used in chemical weapons.

"We have made a very simple first indication ourselves, which showed that this could be (a blistering agent), but this is not accurate, that's why the Americans are here," he said.

Gruenberger said results of the in-depth tests would not be known for several days.

On Saturday, US Brigadier General Mark Kimmitt said up to 40 120 mm shells wrapped in plastic and oozing a potentially toxic substance had been found near the town of Al-Qurna, north of Basra.

"We're doing some preliminary tests on those to be sure that if they do contain any kind of blistering agent they will be disposed of," he told reporters.

Kimmitt, deputy director of operations of the US-led coalition, said the shells were probably left over from the 1980-1988 Iran-Iraq war.

Alleged manufacture of weapons of mass destruction (WMD) was one of the main justifications for last spring's US invasion of Iraq, but despite several false alarms the coalition has found no real evidence of banned weapons.

British Prime Minister Tony Blair suggested Sunday that Saddam Hussein's alleged WMDs may never be found in Iraq.

"In a land mass twice the size of the UK it may well not be surprising you don't find where this stuff is hidden", Blair told BBC television. – Sapa.