Kinshasa, Jan. 12 -- Congo runner-up Martin Fayulu announced on Friday he will file a court challenge to the presidential election results, while his opposition coalition asserted he actually received 61 percent of the vote according to the findings of the influential Catholic Church's observers.

Fayulu spoke to hundreds of supporters who gathered in the capital, Kinshasa, to denounce what they called "the people's stolen victory."

A heavy police presence was on hand. A businessman and vocal campaigner against Congo's widespread corruption, Fayulu accuses outgoing President Joseph Kabila of making a backroom deal with the surprise declared winner, largely untested opposition leader Felix Tshisekedi.

The Catholic Church, the rare author...