A pair of British men are being held in Iran on espionage charges, according to the Iranian News Agency.

The arrested men, Craig and Lindsay Foreman, were allegedly working with “secret institutions affiliated with intelligence agencies of hostile and Western countries.”

Iran’s state-run Mizan news agency reported that the pair were arrested in the southeastern city of Kerman, accused of activities that endangered national security.

According to Iranian authorities, the two Britons “entered the country as tourists but were actually conducting research activities to gather intelligence,” skynews reported.

The couple were on a motorcycle trip to various countries as part of a mission to promote positive psychology, with a final destination of Australia. On social media, Lindsay Foreman had posted posts about their route, noting in December that they would be passing through Iran and Pakistan, two of the “most difficult” parts of their journey.

They allegedly met with the British ambassador

Iranian state media published a photo purportedly showing the couple meeting the British ambassador to Iran, Hugo Shorter. In the picture, two people are sitting opposite the diplomat, but their faces are blurred.

Britain’s warnings on the safety of travel to Iran

The British Foreign Office has issued a warning to its citizens to avoid travel to Iran because of the risk of “arrest, detention and death penalty”. It also advises that travel to Pakistan’s Balochistan, except along the southern coast of the province, should be avoided.

A Foreign Office spokesman said Britain was providing support to the couple and was in contact with Iranian authorities. However, the fate of the two detainees remains uncertain as Tehran has tightened its stance on foreign nationals entering the country under suspicious circumstances.