A Russian court has extended the pretrial custody of an Estonian security officer who faces more than 20 years if convicted of espionage and whose case is at the center of a bitter dispute between Moscow and Tallinn.

Estonia claims Eston Kohver was abducted at gunpoint on Estonian soil by Russian agents and dragged across the border into Russia.

Moscow claims Kohver was seized inside Russian territory carrying cash, weapons, and recording devices while on an undercover operation, and that he had tried to corrupt a Russian official.

The September 5 incident took place just two days after U.S. President Barack Obama visited the Baltic state and NATO ally to provide security guarantees in the face of rising tensions with Russia.

A court in Russia's northwestern Pskov region, which borders Estonia, on June 2 extended Kohver's pretrial custody until August 4.

Kohver's trial is set to begin on June 8 and a court spokeswoman said all further sessions in the case will be closed to the public.

Kohver's state-appointed Russian lawyer, Yevgeny Aksyonov, said on June 2 that the Russian judge hearing the case, Larisa Bobrova, did not have many other cases on her schedule during the summer.

This, according to Aksyonov, would allow the judge to focus on Kohver's case and "conduct the proceedings as fast as possible."

Estonia's consul in Moscow is not being allowed to attend the closed trial.

Aksyonov said the Estonian consul must ask the Pskov court for permission to meet with Kohver in the court's confinement area.

A correspondent from Estonian Public Broadcasting (ERR) who was allowed into the courtroom for 10 minutes before the June 2 session began said Kohver appeared to be in "relatively good shape."

New Charges

The Estonian broadcaster also reported on June 2 that the Russian prosecutors had added a new charge against Kohver -- illegal possession of a weapon -- that could increase his sentence by as much as three years if he were convicted.

Kohver was already facing up to 20 years in prison if convicted on the previously announced charges of espionage, illegal transportation of weapons, and illegally crossing the border into Russia.

Kohver is an officer of Estonia’s internal security service, the Kaitsepolitsei or KaPo.

Administered by Estonia's Interior Ministry, the service is responsible for counterintelligence duties, as well as countering terrorism, protecting state secrets, and preventing the trafficking of weapons and radioactive material.

He has been held at a Russian prison since his September arrest and the Estonian Foreign Ministry has called the case "very disturbing."

Tallinn says Russian agents used a smoke grenade during Kohver's abduction and that markings were later discovered on the ground that prove he was dragged from Estonian territory.

Other than Kohver himself, no witnesses from Estonia have been named to testify in the trial.

Kohver was reportedly trying to meet with a Russian informant as part of an investigation into ties between Federal Security Service (FSB) agents, Russian criminal organizations, and smuggling operations across Russia's border into Estonia.

The European Union has sided with Estonia in the case, calling repeatedly for Kohver's "immediate release" and saying it is "concerned at the abduction" of Kohver "by the Russian security services on Estonian territory."

The EU also has said that Russia’s actions were "against international law and the principle of inviolability of borders."

The United States also has called for Kohver to be "safely" and "immediately" returned to Estonia by Russian officials.

With reporting by TASS and ERR