Democrat Barack Obama easily beat rival Hillary Clinton in Mississippi on Tuesday, giving him new momentum in their heated presidential fight as they head to the next showdown in Pennsylvania in six weeks.

Obama, who would be the first black US president, rode a wave of heavy black support to victory and extended his lead over Clinton in pledged delegates to the August nominating convention. The Illinois senator also won on Saturday in Wyoming.

Clinton revived her hopes in the Democratic race last week by beating Obama in primaries in Ohio and Texas, prolonging their bitter Democratic fight for the right to face Republican John McCain in November's presidential election.