One of two American men arrested in Washington for posing as US federal security officials and cultivating access to the Secret Service, which protects Joe Biden, claimed ties to Pakistani intelligence, a federal prosecutor told a judge.

Justice department assistant attorney Joshua Rothstein asked a judge not to release Arian Taherzadeh, 40, and Haider Ali, 35, the men arrested on Wednesday for posing as Department of Homeland Security investigators.

The men also stand accused of providing lucrative favors to members of the Secret Service, including one agent on the security detail of the first lady, Jill Biden.

Rothstein told the court that in 2019, just months before the two began cultivating security professionals in their Washington apartment building, Ali had travelled to Pakistan, Turkey, Iran and Qatar, and transited Doha multiple times.

In addition, Rothstein said, Ali “made claims to witnesses that he had connections to the ISI, which is the Pakistani intelligence service”.

The Department of Justice (DoJ) is treating the case as a criminal matter and not a national security issue. But the Secret Service suspended four agents over their involvement with the suspects.

“All personnel involved in this matter are on administrative leave and are restricted from accessing Secret Service facilities, equipment, and systems,” the Secret Service said in a statement.

According to an affidavit filed with the court, Taherzadeh and Ali, both US citizens, lived in an apartment building in Washington where numerous federal security-related employees live.

They convinced some of those agents that they themselves were special homeland security investigators, displaying uniforms and documents in support of those claims.

Both were initially charged with one count of false impersonation of an officer of the US, which could bring up to three years in prison.

But Rothstein told the court that the charge could be expanded to conspiracy, which carries a maximum of five years in prison.

The motives of the two men were unclear, but at one point they recruited a third person to work for them, assigning him “to conduct research on an individual that provided support to the Department of Defense and intelligence community”.

Taherzadeh meanwhile provided several Secret Service and homeland security employees with rent-free units costing as much as $4,000 a month, according to the affidavit.

He also gave them iPhones, surveillance systems, a television, and law enforcement paraphernalia, according to the affidavit.

Taherzadeh offered a $2,000 assault rifle to the Secret Service agent who worked on Jill Biden’s team, and did favors for the agent’s wife, including lending her his car.

The affidavit said Taherzadeh and Ali appeared to control several units in the apartment complex, and that Taherzadeh had access to the building’s entire security system.

Like many in law enforcement, the two drove large black GMC-brand SUVs affixed with emergency lights.

Taherzadeh carried handguns that are used by US federal law enforcement, and demonstrated to others that he had secure access to what appeared to be homeland security computer systems.