Image caption The condition of the lorises was "OK, but deteriorating", according to an official

Three men have been arrested in Delhi for trying to board a flight with small primates hidden in their underwear.

Two of the men were found with slender lorises concealed in pouches in their briefs, a customs official at Indira Gandhi International Airport told the BBC.

The men were transit passengers, en route to Dubai from Bangkok.

The animals were uncovered when security guards noticed a bulge in their underwear during a frisk.

The Press Trust of India reported that one of the lorises was 7in (17.8cm) in length.

The condition of the animals was "OK, but deteriorating" according to the official, who declined to be named.

They have been transferred to the Delhi-based organisation People For Animals, which said the lorises were being treated in hospital.

Photographs of the lorises sent to the BBC by the hospital show the red-coated creatures inside an animal transit box lined with newspaper.

Popular pet

Lorises, which are nocturnal and carnivorous primates, are native to parts of South Asia and South East Asia, and live in tropical forest areas.

The slender loris is native to India and Sri Lanka, where experts fear it is becoming extinct.

Lorises have become a popular exotic pet in recent years, despite alarms raised by conservationists that the trade is contributing to their demise in the wild.

Indonesia's loris population has been devastated by the boom in people wanting them as pets.

Conservationists say poachers pull out their teeth - as the primates have a toxic bite - with pliers, making it impossible for them to return to the wild.

The men arrested are all nationals of the United Arab Emirates, according to the customs official, and an investigation into the incident is under way.