A worker inspects the North Korean flagged ship "Chong Chon Gang" docked at the Manzanillo Container Terminal in Colon City July 16, 2013. Panama detained the North Korean-flagged ship from Cuba as it headed to the Panama Canal and said it was hiding weapons in brown sugar containers, sparking a standoff in which the ship's captain attempted to commit suicide. REUTERS/Carlos Jasso

Panama, on Wednesday, charged the 35-member crew of a North Korean ship, which has been detained in Panama since July 10, for endangering public security by unlawfully carrying weapons, BBC reported.

The move came hours after North Korea urged Panama to release the ship and its crew, saying the ship was carrying “nothing but aging weapons which are to send back to Cuba after overhauling them according to a legitimate contract,” according to North Korea’s Foreign Ministry spokesman quoted by the official KCNA news agency.

“The Panamanian investigation authorities rashly attacked and detained the captain and crewmen of the ship on the plea of 'drug investigation' and searched its cargo but did not discover any drug,” the spokesman said.

Panama has asked the United Nations to determine whether the ship was transporting weapons in violation of U.N. sanctions against North Korea, under which supply of arms to Pyongyang is prohibited.

Cuba, from where the ship's journey originated, said earlier that the shipment constituted obsolete Soviet-era weapons being sent to North Korea for repairs along with a cargo of sugar.

Meanwhile, analysts who spoke to USA Today said the shipment discovered by Panama shows that North Korea is trying to expand its foreign ties, and may be gradually reducing its dependence on China.

“Despite years of relations between Cuba and North Korea, there's been no trade of consequence between the two and this seems to indicate there is a new relationship being built between the two countries,” Kim Petersen, president of maritime consultancy Security Dynamics LLC, told USA Today.

At a daily press briefing, U.S. State Department spokesman Patrick Ventrell said the department's non-proliferation bureau is examining the case.

“Any shipment of arms or related materiel would violate numerous U.N. Security Council resolutions,” Ventrell said.