Argentina's government is calling a leading prosecutor a liar for accusing President Cristina Fernandez of secretly negotiating with Iran to avoid punishing those responsible for the country's worst terrorist attack.

Prosecutor Alberto Nisman on Wednesday asked a judge to call Fernandez and Foreign Minister Hector Timerman in for questioning about the 1994 bombing of the Argentine-Israeli Mutual Association in Buenos Aires.

On Thursday, Timerman called the prosecutor's accusations "despicable." He said in a statement that Fernandez has made great strides toward solving the bombing that killed 85 people.

In 2013, Nisman released an indictment accusing Iran and Hezbollah of organizing the blast. Iran denied the charge.

Argentina and Iran later reached an agreement to investigate the attack.

A judge must now decide whether anyone should be summoned.