The United States has been stepping up pressure on Sudan to cut all of its ties with North Korea.In October, US sanctions imposed on Sudan were lifted, but the country was kept on the US' list of "state sponsors of terrorism", along with North Korea, Iran and Syria.

Analysts say Sudan is facing a severe economic crisis and this is likely to have influenced its change of policy.

Sudan's economy is struggling - bread prices doubled earlier this year

US President Donald Trump is expected to meet North Korean leader Kim Jong-un next week, though the US has said sanctions would not be lifted against Pyongyang unless it gave up its nuclear weapons.