Oil prices slid about 2% on Thursday after U.S. President Donald Trump softened threats against Greenland and Iran, and as investors assessed the supply-demand outlook.Brent futures fell $1.01, or 1.6%, to $64.23 a barrel at 11:26 a.m. EDT (1626 GMT). U.S. West Texas Intermediate (WTI) crude fell 96 cents, or 1.6%, to $59.66 a barrel, headed for its lowest close since January 15.