FBI agent denies spying

Hanssen's house in Virginia was searched by the FBI

Former FBI agent Robert Hanssen has made a brief court appearance in the US to deny spying for Moscow.

A plea of "not guilty" was entered on his behalf, and a provisional trial date set for October.

Mr Hanssen is accused of supplying Russia, and before it the Soviet Union, with secrets over a 15-year period, in exchange for payments of $1.4m in cash and diamonds.

"We will be filing motions in federal court attacking this indictment," his lawyer, Plato Cacheris, told reporters outside the District Court in Alexandria, Virginia.

The father of six is accused of identifying Soviet agents secretly working for the United States who were subsequently executed.

He is also charged with passing secrets about satellites, early warning systems, retaliation plans against large-scale attacks and communications intelligence.

Death penalty

Many of the 21 charges against Mr Hanssen carry the death penalty, and the prosecution has so far failed to agree a lesser sentence in exchange for more information about Mr Hanssen's alleged activities.

Questioned outside the courthouse, Mr Cacheris said he was not sure the death penalty would be constitutional in this case.

Hanssen may have informed Moscow about a "spy tunnel" under its US embassy

"Probably not," he told reporters.

Mr Hanssen was arrested in February in a Virginia park, allegedly as he was delivering a package for the Russians. He is being detained at an undisclosed location.

He was escorted to court amid heavy security, wearing a green jumpsuit with the word "prisoner" on the back.

In the past the US Government has avoided taking espionage cases to court because of the fear of airing national security secrets.

Congress brought back the death penalty for spies in 1994 in response to the Aldrich Ames case. Ames, a veteran CIA officer accused of spying for more than eight years for the former Soviet Union, pleaded guilty that year and was sentenced to life in prison.

The US has not sought the death penalty against a spy since the law changed. The last spies executed were Julius and Ethel Rosenberg in 1953.