Moscow's Basmanny court earlier extended Adamov's custody until April 12 during hearings on December 22 that the defendant could not attend because he was in jail in Switzerland fighting extradition to the United States.
Defense lawyer Timofei Gridnev told the court that there were no grounds for keeping Adamov in custody.
"While in jail in Bern [Switzerland], Adamov repeatedly said he wanted to return to his homeland, so the arguments of the Prosecutor General's Office that he may abscond are groundless," he said.
The attorney said the law categorically forbade a court from hearing a case into extending a defendant's term in custody without the accused being present.
However, Valery Lakhtin, a representative of the Prosecutor General's Office, said Adamov faced serious charges and was "a danger to the public".
"On December 31, he [Adamov] refused to testify," Lakhtin said, adding that Adamov was accused of committing a crime in collaboration with a group of individuals currently on the wanted list. He said witnesses in the case might come under pressure if Adamov were released.
The Russian Prosecutor General's Office officially charged Adamov, 63, with embezzlement and abuse of office December 31 in the presence of his lawyers after a long battle to secure his extradition from Switzerland, where he had been arrested at the request of the U.S. in May.
The U.S. authorities accused Adamov, who served as nuclear power minister in 1998-2001, of misappropriating $9 million granted to Russia for nuclear safety projects. He faced 60 years in prison if convicted.
On October 3, the Swiss Federal Justice Department announced it would extradite the former Russian minister to the U.S., but Adamov's defense team filed an appeal with the Federal Tribunal, Switzerland's Supreme Court, in Lausanne in November. On December 22, the Lausanne court upheld the appeal and ruled that the ex-minister be extradited to Russia because the country submitted its extradition request first.
