Two men have been charged in Britain with serious national security offenses following an incident last month near RAF Fairford, the English air base the U.S. military used to launch strikes on Iran. The Crown Prosecution Service announced the charges on Tuesday.

The suspects are Mohmed Abdulkarim and Nouman Essghir, both 24, both British nationals and both residents of London. They were charged under the 2023 National Security Act.

Prosecutors said Abdulkarim faces a charge of "assisting a foreign intelligence service" in September. He is also accused of "engaging in conduct that was likely to materially assist a foreign intelligence service in carrying out U.K.-related activities."

Essghir was charged with a separate national security offense. According to the CPS, he "approached or was in the vicinity of a prohibited place and his conduct was for a purpose that he knew, or having regards to other matters known to him ought reasonably to have known, was prejudicial to the safety or interests of the United Kingdom."

Both men were arrested last week on suspicion of assisting Iran's intelligence service. Counter Terror Police arrested Abdulkarim under the National Security Act at that time, along with a 25-year-old man who holds both British and Iranian nationality. That man was released on bail while the investigation continues.

The wider inquiry into a suspected terror plot against the base is still under way. Five men were first detained on Sept. 27 near the base in western England. All five were released on bail, but police have said they remain under investigation and will be monitored.

On the day of the initial arrests, residents of a nearby town were evacuated from their homes as armed police and bomb-disposal experts searched the area. Officers found gasoline in three vans parked close to an entrance to the base. The vans had been driven by the five initial suspects. No explosives were found.

RAF Fairford has housed U.S. long-range bombers for many years, and it was used to launch strikes on the Islamic Republic during the war with Iran. Iranian officials have repeatedly said that any base used to attack their country would be considered a legitimate target.

The Iranian Embassy in London has denied any link to the incident. In an earlier statement, it said the government in Tehran "categorically rejects and strongly condemns the recent unfounded and malicious speculations published by some British individuals and media outlets attempting to link Iran" to the episode.

Police said on Tuesday that six men remain free on bail in connection with the case. Four of them were arrested on Sept. 27, and all are U.K. nationals in their 20s who live in London. The other two were detained later, including the 25-year-old British-Iranian dual national who was held on Oct. 1.