WASHINGTON - US President Barack Obama extended sanctions against the Democratic People's Republic of Korea (DPRK) for another year on Thursday.

In a message to the US Congress, Obama said the existence and the risk of the proliferation of weapons-usable fissile material on the Korean Peninsula, and Pyongyang's actions and policies "continue to constitute an unusual and extraordinary threat to the national security, foreign policy, and economy of the United States.

"For these reasons, I have determined that it is necessary to continue the national emergency with respect to these threats and maintain in force the measures taken to deal with that national emergency," he said.

The national emergency, first declared on June 26, 2008, by then US president George W. Bush, was due to expire automatically on the anniversary date of its declaration unless the incumbent president announced its continuation.

The Obama administration has not only kept extending the emergency, but also imposed tougher sanctions on Pyongyang in April, including a ban on direct and indirect imports of goods from the DPRK.

In another development, the DPRK's Korean Central News Agency sent a delegation, led by its General Director, Kim Pyong-ho, to the United States on Thursday at the invitation of the Associated Press (AP).

According to Yonhap news, the unprecedented trip came three months after Tom Curley, president and CEO of AP, visited Pyongyang and met top officials.

Meanwhile, visiting Foreign Minister of the Republic of Korea Kim Sung-hwan was scheduled to hold talks with US Secretary of State Hillary Clinton on the DPRK nuclear issue on Friday.