A judge in Argentina has refused to investigate the possible involvement of the head of the country's armed forces and two government ministers in illegal arms sales to Ecuador and Croatia.

The judge, Jorge Urso, was ordered by a Buenos Aires court on Wednesday to widen his two-year inquiry to include the three men.

But he now says the court has no power to tell him who he should investigate.

Correspondents say that despite official backing for the three men, the case has caused the government of President Carlos Menem considerable embarrassment.