Pakistani security officials have arrested a man at Karachi airport after he was found with batteries and electrical circuits hidden in his shoes as he was trying to board a flight, officials said on Monday.
The bearded man, identified as Faiz Mohammad, 30, was about to board a Thai Airways flight to Muscat late on Sunday when the devices were found during a routine security check.
He was not carrying any explosives nor were any other suspicious items found on him or in his luggage, an airport security official said.
Police said they were investigating.
"The suspect has told us that it was nothing but a massager, but we are looking at all possible angles, including terrorist activities," said senior police official Tanveer Alam Odho.
In late 2001, a British Islamist militant, Richard Reid, tried to blow up an airliner over the Atlantic with explosives in his shoes.
Pakistan is at the centre of international worries over Islamist militant bomb plots.
A Pakistan-American was arrested in the United States a week ago over a botched plot to blow up a car-bomb in New York's Times Square. The United States is convinced that Pakistani Taliban militants allied with al Qaeda were behind that.
The man arrested in Karachi had placed two batteries hooked up to wires in cavities cut into the heels of each of his shoes.
The devices could have been used to set off explosives, said the airport security official, who declined to be identified.