A court in Russia’s far eastern city of Vladivostok has started the trial of a US soldier arrested in the city earlier this year on charges of stealing.

Staff Sergeant Gordon Black, 34, flew to the Pacific port city to see his girlfriend and was arrested after she accused him of stealing from her, according to US and Russian officials.

He faces up to five years in prison if convicted.

Russian state news agency RIA Novosti reported from the courtroom in Pervomaisky District Court in Vladivostok on Thursday that Black has agreed to give evidence in the trial and will respond to the accusations against him later in the proceedings.

The report cited local police as saying that Black is co-operating with the authorities.

His arrest further complicates US relations with Moscow, which have grown increasingly tense as the fighting in Ukraine continues.

Russia is holding a number of Americans in its jails, including corporate security executive Paul Whelan and Wall Street Journal reporter Evan Gershkovich. The US government has designated both men as wrongfully detained and has been trying to negotiate their release.

Other detainees include Travis Leake, a musician who had been living in Russia for years and was arrested last year on drug-related charges; Marc Fogel, a teacher in Moscow who was sentenced to 14 years in prison, also on drug charges; and dual nationals Alsu Kurmasheva and Ksenia Khavana.

The US State Department strongly advises American citizens not to go to Russia.

Under Pentagon policy, service members must get clearance for any international travel from a security manager or commander.

The US Army said last month that Black had not sought clearance for the international travel and it was not authorised by the Defence Department. Given the hostilities in Ukraine and ongoing threats to the US and its military, it is extremely unlikely he would have been granted approval.

Black was on leave at the time and in the process of returning to his home base at Fort Cavazos, Texas, from South Korea, where he had been stationed at Camp Humphreys with the Eighth Army.

Cynthia Smith, an Army spokeswoman, said Black signed out for his move back home and, “instead of returning to the continental United States, Black flew from Incheon, Republic of Korea, through China to Vladivostok, Russia, for personal reasons”.

Black’s girlfriend, Alexandra Vashchuk, told reporters after the court hearing on Thursday that “it was a simple domestic dispute” during which Black “became aggressive and attacked” her.

“He then stole money from my wallet and I didn’t give him permission to do it,” she said.

US officials have said that Black, who is married, met his girlfriend in South Korea.

According to US officials, the Russian woman had lived in South Korea, and last autumn she and Black got into a domestic dispute or altercation, after which she left South Korea.

It is not clear if she was forced to leave or what, if any, role Korean authorities had.