A former FBI informant charged with making up a multimillion-dollar bribery scheme involving President Joe Biden, his son Hunter and a Ukrainian energy company had contacts with Russian intelligence-affiliated officials, prosecutors said in a court paper Tuesday.

Prosecutors revealed the alleged contact as they urged a judge to keep Alexander Smirnov behind bars while he awaits trial. He’s accused of falsely telling his handler that executives with the Ukrainian energy company Burisma paid Hunter and Joe Biden $5 million each around 2015. The claim became central to the Republican impeachment inquiry in Congress.

U.S. Magistrate Judge Daniel Albregts allowed Smirnov to be released from custody on electronic GPS monitoring while he awaits trial. He must stay in Clark County, Nevada, and is prohibited from applying for a new passport.

Prosecutors said Smirnov, 43, admitted during an interview after his arrest last week that “officials associated with Russian intelligence were involved in passing a story” about Hunter Biden. They said Smirnov’s contacts with Russian officials were recent and extensive, and said Smirnov had planned to meet with one official during an upcoming overseas trip.