Washington - The US military is reportedly tracking a North Korean vessel suspected of carrying illicit weapons in violation of a UN Security Council resolution.

The chairman of the Joint Chiefs of Staff, Admiral Michael Mullen, told reporters Thursday the United States and other countries have authority under the resolution to inspect a "vessel like this" but provided no details.

"We intend to vigorously enforce the United Nations Security Council Resolution 1874 to include options, to include certainly and hail and query," Mullen said.

FOX News, citing an unnamed senior US military source, reported the North Korean ship, the Kang Nam, left the country on Wednesday and is being monitored by US forces in the air.

A spokesman for the Hawaii-based US Pacific Command refused to comment on the report.

The ship could be carrying weaponry, missile parts or nuclear materials or related technology, FOX said.

One military source told FOX News the Kang Nam has been suspected of proliferated illicit cargo in the past and is "a repeat offender."

The Security Council passed the resolution following North Korea's recent underground nuclear detonation, which has raised tension with Washington and was greeted with worldwide condemnation.

The resolution calls for the boarding of North Korean ships after receiving permission but prohibits the use of force to carry out the inspection, leaving the US military in a quandary about how to enforce the resolution on a non-compliant ship.

One option is to wait until it reaches a refuelling port. Under the resolution, the host country is required to carry out the inspection and report to the Security Council.

"The country of that port is required to inspect the vessel and to also keep the United Nations informed, obviously, if a vessel like this would refuse to comply," Mullen said.

North Korea has declared that an uninvited inspection of its should would be an act of war and that it would respond appropriately.(dpa)