The United States has extended economic sanctions against North Korea for another year as tensions grow over its nuclear activities.
Barack Obama, the US president, moved on Wednesday to prolong restrictions on property dealings with the North that were due to expire on Friday.
Obama said he acted "because the existence and risk of the proliferation of weapons-usable fissile material on the Korean peninsula continue to pose an unusual and extraordinary threat to the national security and foreign policy of the United States".
Last year, George Bush, the former president, rescinded the Trading with the Enemy Act for North Korea, which had banned all commerce with Pyongyang on the grounds that it was a "hostile state".
Only Cuba remains on the list.
But Bush had, at the same time, slapped restrictions for one year on property dealings with North Korea, which would have otherwise been lifted.
Despite the Obama administration saying that it would welcome fresh talks with the North, relations with the communist state continue to deteriorate amid international condemnation and sanctions in response to its recent nuclear test, and defiant rhetoric from Pyongyang.
The extension of US sanctions comes as Hillary Clinton, the US secretary of state, called the foreign ministers of Russia and China to discuss efforts to enforce UN-backed punishments for North Korea's nuclear test.
Ian Kelly, a department spokesman, would not discuss whether Yang Jiechi, the Chinese foreign minister, and Clinton talked about a US destroyer following a North Korean ship along China's coast.
According to some reports, the North Korean freighter, the Kang Nam, is carrying weapons including missiles and missile parts bound for Myanmar.
The Kang Nam is the first North Korean ship to be monitored under new UN sanctions that authorise member states to inspect North Korean sea, air and land cargo.