The crew members will face court Monday on charges of transporting weapons of war. The arrests followed cooperation with international intelligence agencies who had been tracking the aircraft over the past week.
The Ilyushin II-76 aircraft and crew of five, detained over the weekend, are due to face a Thai court Monday on charges of transporting weapons of war into Thailand without authorization.
The five men - one from Belarus and four from Kazakhstan - were detained Friday when the plane made a stop in Bangkok to refuel after flying from the North Korean capital of Pyongyang.
Reports say authorities uncovered 35 tons of weapons onboard the aircraft when it was seized by authorities at Bangkok's secondary airport of Don Mueang. The crew had reported its cargo as oil drilling equipment.
Panitan Wattanayagorn is the Thai Government spokesman.
"The five men - as you know one has a passport from Belarus - that's believed to be the pilot maybe and four from Kazakhstan - deny all charges and they'll be sent to court tomorrow on two major charges," Panitan said. "One - in the possession of weapons of war - and second the bringing in those weapons of war into the Kingdom without proper authorization."
Panitan said the final destination of the aircraft was still being investigated but the plane had travelled by way of Sri Lanka and Bangkok earlier in the week before making its return flight from North Korea.
Mr. Panitan said the authorities would make a closer inspection of the weapons Tuesday. But reports said the cargo had included rocket-propelled grenades, missiles and rocket launchers, missile tubes, surface to air missile launchers, as well as spare parts.
The Thai Government, he said, was acting under two United Nations resolutions which called on the Thai Government to verify the cargo, to seize the cargo and also to destroy weapons found on board.
North Korea is facing fresh United Nations sanctions after carrying out a nuclear test in May of this year. The tougher sanctions are aimed at cutting off North Korea's access to foreign exchange from arms sales reported to earn the country up to $1 billion a year.
North Korea faces widespread criticism over allegations of violating United Nations sanctions by selling weapons to nations in Africa, Asia and Latin America. Major arms sales have involved ballistic missiles, with Iran and other Middle East states reported to be among the key customers.