Oren Dorell, @OrenDorell

USA TODAY

Panama%3A North Korean-flagged ship had ballistic missiles and other arms

Panama says it seized the ship as it set sail from Cuba

Ship%27s captain suffered heart attack%2C tried to commit suicide%2C Panamanian president says

Missile radar systems discovered aboard a North Korean-flagged ship that had last been in Cuba could be upgraded to make air-defense systems more effective at shooting down modern military aircraft, military analysts said Tuesday.

The North Korean ship was seized after inspectors found weapons system parts under sacks of sugar as it sought to cross the Panama Canal on its way to its home country, Panamanian President Ricardo Martinelli said Tuesday. North Korea is under a United Nations arms embargo.

Patrick Ventrell, a State Department spokesman, said the department's non-proliferation bureau is looking into the case. "Any shipment of arms or related materiel would violate numerous U.N. Security Council resolutions," he said.

Defense experts said images released by Panama indicate the cargo is a radar system for the SA-2 family of surface-to-air (SAM) missiles, which are designed to shoot down enemy aircraft at high elevations.

John Pike of Globalsecurity.org said that ever since an SA-2 shot down Gary Powers' U-2 spy plane in 1960, American engineers have worked "to render this missile ineffective."

"I think the United States and South Korea and Japan have reasonable confidence they can jam it and blow up its radars and it can be rendered ineffective, but it could not be ignored," said Pike, whose group monitors weapons threats globally.

Panama had not verified where the radar system came from or where it was headed ultimately. Cuba and North Korea issued no statement on the discovery.

The radar was developed by the former Soviet Union, which was dissolved in 1991, but the system is "still in use in a lot of countries, and progressive upgrades to the radars and the missiles means it is not completely useless," said James Hardy, Asia-Pacific editor of IHS Jane's Defense Weekly.

Modern jamming techniques prevent such a radar from getting a fix on an aircraft but "counter-counter-electronic measures have been fitted to later, post-Soviet models of this radar," Hardy said.

Modernizing the radars would involve changing analog systems to digital and upgrading the software to make them less vulnerable to electronic jamming and spoofing, according to IHS Jane's.

Martinelli said the ship that was transporting the cargo is the Chong Chon Gang. The crew resisted efforts to search and seize the ship, and the captain had a heart attack and attempted suicide during the operation, Martinelli said.

The equipment could have been sent from Cuba to North Korea for an upgrade, to be returned to Cuba and to be paid for with the sugar, or it could be an arms shipment to North Korea, IHS Jane's said.

Bruce Bechtol, a former intelligence analyst for the Defense Intelligence Agency, said the seizure uncovered the first confirmed shipment of weaponry from Cuba to North Korea since the end of the Cold War.

Although North Korea already has many SA-2 missiles, "you can always use more," said Bechtol, author of The Last Days of Kim Jong-il: The North Korean Threat in a Changing Era. The SA-2s "shoot down fighter aircraft quite effectively," Bechtol said.

Contributing: The Associated Press