(CNN) -- A man who was arrested at an airport in Pakistan with shoes that contained batteries, a circuit board and an on/off switch said Monday that he did not know the materials were in his shoes.
Faiz Mohammed said he had worn the same shoes while traveling from Muscat, Oman, where he worked as a construction supervisor, to Karachi, Pakistan, in February.
Investigators in Karachi arrested Mohammed on Sunday after a scanner sounded an alarm as he prepared to board a Thai Airways flight to Muscat. They said they did not find explosives.
Mohammed spoke with a journalist Monday at a police station in Karachi.
Haji Hassan of Karachi Airport, meanwhile, told CNN on Monday that authorities have filed no formal charges against Mohammed. Hassan said authorities continue to investigate the man they have described as a 30-year-old civil engineer.
There was no immediate indication from Pakistani security officials Sunday on what they thought the intended use of the batteries and other materials might have been.
Officials said the man told interrogators he had come from Pakistan's Khyber-Pakhtunkhwa Province, until recently called North West Frontier Province, an area where Taliban and militants have a presence.
The man lives in East Karachi, officials said.
CNN's Tommy Evans and journalist Shad Khan contributed to this report.