Scientists are testing traces of nerve agents and mustard gas found at a US air base in Uzbekistan, US military sources said today.
The base is being used by coalition troops in their campaign against al-Qaeda and Taliban fighters in neighbouring Afghanistan.
"Routine environmental monitoring efforts at Karshi Khanabad air base in Afghanistan have discovered traces of possible nerve agents at two locations on the base and a suspected blister agent at another," US spokesman Colonel Roger King said in a statement.
Troops had been moved from the areas but there was no evidence that any coalition members had been affected, Col King added in the statement from Bagram Air Base.
A US military spokeswoman in Tampa, Florida, said scientists were testing the traces to find out if they were leftovers from Soviet use of the base, which now houses some 1,000 coalition forces, or if they had been recently introduced.
The traces of nerve gas were found near a building used as a headquarters for troops and in an unoccupied part of the base.
The blister agent, which is more commonly known as mustard gas, was discovered near a hangar used for aircraft maintenance.
Uzbek officials had informed members of a visiting US army health team that the agents appeared to have been stored some time ago.
"There are no confirmed cases of nerve agent or blister agent exposure among US and coalition members," Col King said.
AFP