WASHINGTON (Reuters) - U.S. Secretary of State Rex Tillerson urged African leaders on Friday to take further actions to pressure North Korea to end its nuclear and missile programs, including downgrading diplomatic ties and expelling North Korean laborers.  All nations must act to implement U.N. sanctions in full,  Tillerson told a trade and security gathering with African ministers.  Further, I urge you to take additional measures to pressure the DPRK by downgrading your diplomatic relationships with the regime, severing economic ties, expelling all DPRK laborers and reducing North Korea s presence in your country.  The U.S. State Department said on Thursday that Sudan had committed to severing trade and military ties with North Korea. 
U.S. urges African nations to press North Korea over nuclear program