Six passengers were arrested at Calcutta airport for allegedly smuggling gold weighing 10.7kg and valued at Rs 4.1 crore early on Tuesday, said customs officials.

The gold was concealed in checked-in baggage in the form of wires coated with metals. “The gold wires were concealed along the metal reinforcement strips inside the checked-in baggage to avoid detection during scanning,” said a customs official.

Three passengers had arrived in Calcutta from Riyadh through Abu Dhabi, while three others came from Dubai, said officials.

Sources said the six were from states including UP and Bihar and were working in Riyadh and Dubai. After being arrested, the six claimed they had no idea that the six pieces of baggage contained gold.

“They claimed that someone else had asked them to bring the baggage to Calcutta and hand it to another set of people outside the airport,” said a customs official.

At the Calcutta airport, passengers had been caught over the last few years bringing in gold concealed inside LCD/LED TVs, torches and even inside the rectum. Officials said smuggling had increased since 2013 after the import duty on gold was raised.

Often pouches containing gold bars were found in washrooms of aircraft which were left by passengers of an earlier flight to be picked up by someone else when the aircraft would operate in another sector.