U.S. federal prosecutors are charging the father of an admitted terrorist with lying to investigators and hiding evidence in the case of his son, who plotted to bomb the New York City subway system.

Afghanistan-born U.S. citizen Mohammed Zazi pleaded not guilty Monday to two counts of obstruction of justice and conspiracy.

Prosecutors at the U.S. District Court in New York state say Zazi thwarted an investigation by the FBI by lying and destroying chemicals and other evidence used by his son, Najibullah Zazi. The elder Zazi has denied the charges.

Najibullah Zazi pleaded guilty in February to the 2009 subway plot. He is awaiting sentencing.