WASHINGTON (Yonhap News) -- The United States has "concerns" that a North Korean ship recently intercepted by a U.S.

destroyer might have been carrying contraband weapons in breach of U.N. Security Council resolutions, the State Department said Monday.

"There was a vessel that was suspected of carrying materials prohibited by the United Nations Security Council resolutions,"

spokesman Mark Toner said in a press briefing, confirming media reports.

North Korea is banned from selling or buying most weaponry under the resolutions adopted for its nuclear and long-range missile tests in 2006 and 2009.

In the latest known case, the North Korean freighter apparently en route to Myanmar was intercepted south of the Chinese city of Shanghai on May 26. The resolutions call upon all states to inspect cargo to and from North Korea if they have "information that provides reasonable grounds to believe the cargo contains" illicit weapons.

Toner would not get into details on what the vessel was carrying, but he said there is good reason to suspect illegal trade. The ship's master denied authorities permission to board and to inspect the cargo, he pointed out. He added the ship turned around and headed back to North Korea.

The fact "speaks to some of our concerns about its cargo," he said. "We talked directly with the North Koreans to stress the importance of not engaging in proliferation-related transfers."

The case was a reminder of the U.S. resolve to abide by the U.N. sanctions on Pyongyang and put pressure on it amid a drawn-out stalemate in efforts to dismantle its nuclear weapons program.

On a visit to Seoul earlier this week, meanwhile, Gary Samore, a senior White House official, revealed that the U.S. Navy had intercepted the North's ship.

In an interview with Yonhap News Agency, Samore, the Obama administration's coordinator for arms control and weapons of mass destruction, proliferation and terrorism, identified the ship as "The Light," saying it was believed to be heading toward Myanmar carrying military-related contraband, such as small arms or missile-related items. (Yonhap News)