Two men were arrested at Schiphol airport in Amsterdam this morning following concerns they were preparing a terrorist attack.

The men, who have been named as Ahmed Mohamed Nasser al-Soofi and Hezam al-Murisi by ABC News in the US, were arrested after flying from Chicago on a United Airlines flight.

It is thought the men were allowed to fly despite US authorities detecting a number of suspicious items, including a mobile phone taped to a bottle, watches, a box cutter and knives as well as $7,000 in cash, in their luggage.

However, US authorities said the items, despite being suspicious, were not intrinsically dangerous and the two men were not carrying any banned objects in their hand luggage.

US air marshalls were also onboard the two men’s flight.