BRATISLAVA (Reuters) - Slovakia’s Interior Ministry will allow police officers to testify in an investigation into the case of a former Vietnamese business executive who Germany says was kidnapped by Vietnamese agents in Germany and smuggled back home through Slovakia.

The alleged incident took place during a visit to Slovakia by Vietnamese public security minister To Lam in July 2017.

German prosecutors have said businessman Trinh Xuan Thanh, who had sought asylum in Germany, was abducted in a Berlin street by Vietnamese secret service agent and taken back to Vietnam, where he was tried and jailed for life.

On Thursday, the daily Dennik N cited several Slovak police officers as confirming Thanh was smuggled to Vietnam on a Slovak government plane.

Thanh was taken in a van from Berlin via Prague to Bratislava, where was added to the Vietnamese minister’s delegation and left on a Slovak government plane, according to the Dennik N report.

The case soured relations between Germany and Vietnam and prompted Germany to accuse Vietnam of breaching international law. A German court in July sentenced a Vietnamese man to three years and 10 months in jail after he confessed to helping his country’s secret services kidnap Thanh.

Slovakia has sought to distance itself from the incident and former interior minister Robert Kalinak on Friday denied any involvement in the kidnapping, calling the story “science-fiction”.

On Monday, the Interior Ministry said in a statement: “Interior Minister Denisa Sakova decided on August 6 that (the policemen) will have their discretion lifted in the case of information on the kidnapping of a Vietnamese citizen from Germany to Vietnam”.

The allegations have strained Slovakia’s three-party ruling coalition. Junior partner Most-Hid party said on Monday it could not stay in the coalition if the media reports about the case were confirmed.

Prime Minister Peter Pellegrini said on Friday he would send Sakova and police chief Milan Lucansky to Germany to cooperate with Berlin police.