KABUL, June 9: Scientists are testing traces of nerve agents and mustard gas found at a US air base in Uzbekistan, United States military sources said on Sunday.

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, King added in the statement from Bagram Air Base about 50 kilometres (31 miles) north of here.

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.

“They have very sophisticated tests. Pending the outcome, I’m sure they will be able to determine if it was left over from many, many years ago,” or not, Lieutenant Colonel Judy Desantis told AFP.