A North Korean vessel bound for Burma last month turned back to port after being tracked by a US naval ship on the South China Sea, according to the New York Times who reported that US officials suspected it was carrying arms.

US officials were also alerted to the registration of the ship. “This case had an interesting wrinkle: the ship was North Korean, but it was flagged in Belize,” one told the newspaper.

The US navy destroyer, McCampbell, caught up with the MV Light south of Shanghai on 26 May. It had allegedly been tracked by US officials due to suspicions that it was used in previous arms exports from North Korea, which is subject to the US-sponsored UN Security Council resolution 1874 and subsequent arms embargos that came about after an alleged nuclear test in 2009.

The US vessel reportedly asked to board the MV Light four times but was refused by the crew. The McCampbell was apparently unwilling to forcibly board the ship, despite being given the go-head by authorities in Belize who are signatories to a Bush-era anti-proliferation agreement known as the Proliferation Security Initiative.

As the New York Times reported, the US was wary of inciting war on the volatile Korean peninsula, and also of the diplomatic embarrassment if the cargo proved to be legal.

The incident coincided with a visit by an ASEAN delegation to Washington which included a Burmese official. The delegation was briefed by senior White House nuclear advisor Gary Samore, who showed officials a picture of the vessel and expressed Washington’s concerns. “The Burmese official in the room protested that we were making accusations,” according to an anonymous New York Times source.

After the McCampbell’s inability to board the MV Light, the vessel was tracked by surveillance planes at least until Samore’s briefing in Washington on 27 May. Within a few days the MV Light returned home, reportedly with engine trouble.

The incident was similar to the case of the Kang Nam II in June 2009, which was also tracked by the US navy and forced to turn back.

Despite the two successful interceptions, the North Koreans are widely suspected of assisting the Burmese in weapons programs. With suspicion focusing on alleged missiles and military tunnels, the fear as ever is that relations of this sought will see the North Koreans, like Germany, become party Burma’s nuclear program. This was highlighted in a Wikileaks cable released late last year.

Five rocket sites are alleged to have been built by the Burmese military with the assistance of Russia, and stocked with North Korean equipment including 122mm rockets.

The Burmese recently rejected accusations of a nuclear program, brought to light in a DVB investigation last year, when they told visiting US senator John McCain that the country was “too poor” to obtain or develop such technology.