Liberia's main opposition party says it has chosen a Harvard-trained lawyer to challenge the incumbent, a Harvard-trained economist and Africa's only female head of state, in an October poll.

Winston Tubman said Sunday the Congress for Democratic Change chose him to contest President Ellen Johnson Sirleaf for a six-year term. Former international soccer player George Weah will run as Tubman's vice president.

Tubman and Weah both ran for president in 2005, with Weah losing to Sirleaf in a runoff.

Tubman has worked in senior Liberian government positions and for the United Nations.

Liberia was ravaged by civil wars for years until 2003. The country is still struggling to maintain a fragile peace with the help of U.N. peacekeepers.