An aging North Korean freighter carrying suspected missile-system components hidden beneath bags of sugar was seized in Panama last week on its return from Cuba, Panamanian officials announced Tuesday.

The Chong Chon Gang, a rusting, 14,000-metric-ton ship that carries a painted North Korean flag, was traveling through the Panama Canal last week when it was intercepted and boarded by drug enforcement agents who had received a tip that it was smuggling narcotics.

In dramatic scenes described by Panamanian President Ricardo Martinelli, officers were met with violent resistance from the 35-strong crew during efforts to redirect the vessel to port and the ship’s captain subsequently tried to commit suicide. He is hospitalized in stable condition after slitting his throat with a knife, according to wire reports.

Martinelli, who used his Twitter account to post a photograph, taken in the ship’s hold, of a long green missile-shaped object, told local radio that “sophisticated missile equipment” had been discovered.

“That is not allowed,” he said. “The Panama Canal is a canal of peace, not war.”

Panamanian workers stand atop sacks of sugar inside a North Korean-flagged ship at the Manzanillo International container terminal on the coast of Panama on Tuesday. (Arnulfo Franco/AP)

The ship’s concealed cargo appears to be in breach of U.N. sanctions that prevent North Korea from exporting weapons and from importing all but small arms.

Officials arrested the crew Monday after making the discovery and are removing 250,000 bags of sugar so they can thoroughly inspect the ship, a process they say may take up to a week.

The United States said it “strongly supports” the decision to intercept the freighter.

Late Tuesday, the Cuban Foreign Ministry said in a statement that the ship was carrying 240 metric tons of “obsolete defensive weapons” to be repaired in North Korea and returned to Cuba. It listed the weapons as two Volga and Pechora antiaircraft missile systems, nine missiles “in parts and spares,” two Mig-21 aircraft and 15 engines for the planes — “all of it manufactured in the mid-twentieth century.”

The statement also said Cuba has “unwavering commitment” to peace, nuclear disarmament and international law.

North Korea had not commented on the incident.

The 450-foot-long Chong Chon Gang was tracked leaving the Russian port of Vostochnyy on April 12 and entered the Panama Canal at the start of June with Havana as its stated destination, the maritime company Lloyd’s List Intelligence said.

Crew members appear to have turned off the ship’s automatic tracking system for the voyage. The ship did not reappear until July 11, when it was diverted to Manzanillo, Panama.

Hugh Griffiths, a maritime arms trafficking expert based at the Stockholm International Peace Research Institute, said in an interview Tuesday that he had been monitoring the vessel since 2010, when it was detained by Ukrainian authorities who discovered small-arms ammunition, light weapons and narcotics on board.

Before the most recent incident, Griffiths said, the freighter had last used the Panama Canal in 2002 and had not sailed in the Western Hemisphere since then.

“Until April of this year it was being logged in Chinese ports, and before that it traveled to places in the Indian Ocean like Bangladesh, Iran and Pakistan,” he said.

Griffiths said the Chong Chon Gang’s voyage was highly unusual. “The North Korean fleet is on a safety watch list, so they’re inspected very frequently, and they’re also, of course, on arms trafficking watch lists,” Griffiths said. “. . . It’s pretty crazy, sending a ship to Cuba. It’s very obvious.”

The discovery follows recent signs that North Korea is attempting to foster a closer relationship with Cuba. This month, the head of the North Korean armed forces visited Cuba and met with President Raúl Castro.