International athletics chiefs said yesterday that legal problems had stopped the United States from suspending shot putter Randy Barnes and sprinter Dennis Mitchell despite positive drug tests.

The sport's governing body, the International Amateur Athletic Federation (IAAF), said American civil law had prevented the US ruling body from following the IAAF in taking immediate action against two of the country's leading athletes.

The IAAF has suspended world record putter Barnes and 1992 Olympic 100 metres bronze medallist Mitchell after they failed IAAF out-of-competition tests at the start of April. They now await confirmation of the results from their B-samples.