A security guard working at the US embassy in Norway has been arrested on suspicion of spying for Russia and Iran, a Norwegian police official said on Thursday.

The man, a Norwegian citizen in his 20s, was arrested at his home on Wednesday, police said. On Thursday, a court ruled that he should be detained for the first four weeks, with the first week in solitary confinement, while police investigate.

“The defendant was an employee, a guard, at the US embassy in Oslo,” Thomas Blom, a lawyer for the police security service PST, told reporters.

The man was cooperative and talking with officers, Blom said, adding that a “large” amount of digital material was seized.

“We’ve just scratched the surface and we’re trying to take it further,” Blom said.

The man’s lawyer, John Christian Elden, said his client had been in contact with Russian and Iranian intelligence officers.

“He was explained about his contact with intelligence agents from Russia and Iran, but it is unclear whether he had classified information for which anti-espionage laws could be used against him,” Elden told Reuters.