Germany’s defense minister has canceled a visit to the US to focus on the arrest of an army officer suspected of planning a racially motivated attack. Authorities believe the man was part of a network of up to five people, according to German media.

Ursula von der Leyen was scheduled to travel to New York and Washington DC on Wednesday and Thursday for meetings with US Defense Secretary Jim Mattis and UN officials. However, she canceled the trip to focus on the arrest of a German army officer referred to as Franco A., who is suspected of planning a right-wing terrorist attack.

Germany’s chief federal prosecutor’s office said on Tuesday there were “preliminary indications of preparations for a serious attack against the state.”

The 28-year-old officer was arrested in the German city of Hammelburg last week, on suspicion of hiding a gun in a bathroom at Schwechat airport in Vienna.

Investigators later discovered he had used a fake identity to successfully register as a Syrian refugee, despite not speaking any Arabic, raising concerns that he was attempting to carry out an attack to frame refugees.

Defense Ministry officials have since found Nazi memorabilia, swastikas, and Nazi symbols at the barracks where Franco A. was stationed, according to various media reports.

Bild has reported that police also found a “deathlist“ allegedly compiled by the suspect, which included left-wing anti-fascist activists.

A 24-year-old student and alleged co-conspirator in possession of explosives was also arrested last week, with prosecutors saying that both men harbored “xenophobic views.”

However, the 24-year-old may not have been Franco A.’s only co-conspirator. Germany’s Hannoveriche Allgemeine newspaper reported on Tuesday that the Defense Ministry now believes Franco A. was part of a network consisting of up to five people.

Meanwhile, Germany’s Armed Forces Association (Bundeswehrverband) and political opponents have lashed out at von der Leyen after she told ZDF on Sunday that the country’s army has an “attitude problem” and “clearly has a weakness of leadership on several levels.”

“No one can understand how a defense minister can walk away from the match and criticize her own team, so to speak,” Armed Forces Association spokesman André Wüstner told broadcaster MDR on Tuesday, describing the comments as “unbelievable.”

Those thoughts were echoed by Rainer Arnold, defense policy spokesman for the Social Democrats (SPD), who demanded an apology from the defense minister.

“That she accuses the whole army of having an attitude problem leaves me speechless. Every honest soldier feels insulted,” Arnold said, as quoted by the Local.

The investigation surrounding Franco A. has been handed over to the office of Germany’s chief federal prosecutor, with a spokesman on Tuesday citing “preliminary indications of preparations for a serious attack against the state.”