Congo, Jan. 20 -- Congo's election crisis deepened early Sunday when the Constitutional Court confirmed the win of Felix Tshisekedi, rejecting claims of fraud, and runner-up Martin Fayulu promptly declared himself the country's "only legitimate president."

Fayulu's supporters have alleged an extraordinary backroom deal by outgoing President Joseph Kabila to rig the vote in favor of the opposition after the ruling party's candidate did so poorly that a Plan B was needed. Neither side has acknowledged the accusations.

The court, however, said Fayulu offered no proof to back his assertions that he had won easily based on leaked data attributed to the electoral commission.

Fayulu urged Congolese to take to the streets to peacefully protest...