Two British nationals were detained by security agencies at a five star hotel near the Indira Gandhi International airport in New Delhi after they were believed to be indulging in 'suspicious' activities, police said on Tuesday.
The foreigners were detained on Monday after officials of Raddison Hotel in south-west Delhi's Mahipalpur became suspicious about the activities of Stephen Hampston (46) and Steve Martin (55), who had checked in four days ago.
"We detained them because of suspicious activities," Delhi Police Commissioner Y S Dadwal told reporters. However, he refused to provide details about them.
Police sources said the duo, who were suspected to be tracking the movement of flights arriving and departing from the international airport, were allegedly in possession of powerful binoculars and other sophisticated equipment.
Investigators of Delhi Police's Special Cell and Intelligence Bureau rushed to the spot and questioned them.
Police is also probing an email believed to have been sent by Hampston.
Home ministry sources said the Britishers have been confined to the hotel.
Most of the agencies involved in the investigation have given clearance to the software found in the possession of the two British nationals, they said.
Sources said the British High Commission has been informed about the detention.
The Britishers were said to be carrying a sophisticated gadget which could be attached to an antennae and used to monitor air traffic and capture the details of any aircraft, including military ones.
The two detained persons said aircraft spotting was their hobby and they use these equipment for this purpose, the sources said.
"We are verifying their claims. The equipment which is believed to have the capacity to track an aircraft which is around 100 km away is being examined by experts. We are also verifying their passport details," a senior police official said.
Investigators are also trying to ascertain whether they were in touch with any other person in Delhi or other parts of India.
"We are looking into their call details. Their mobile phones and laptops are being examined besides their emails," the official said.
This is the second incident of a foreign national being detained in the capital in past one week.
American citizen Winston Marshall Carmichael was detained at the airport in New Delhi on February 9 after security personnel found a knife in his hand baggage.
Though no terror link has been established in his case so far, Carmichael is lodged at the Lampur detention facility in the capital.