NEW YORK — A prosecutor says 10 defendants accused of spying for Russia want to plead guilty.

The pleas are expected to set the stage for the largest Russia-U.S. spy swap since the Cold War. The pleas are taking place today, hours before defendants are to be returned to Russia.

The prosecutor, Michael Farbiarz, made the announcement at the start of a hearing in federal court in Manhattan at which 10 defendants appeared before Judge Kimba Wood. An 11th defendant was a fugitive after he fled authorities in Cyprus following his release on bail.

The arrests occurred more than a week ago, capping a decade-plus investigation of people who seemed to have embedded themselves in the fabric of American life. Authorities said they were reporting what they learned in the U.S. to Russian officials.