Updated

The African Union envoy in charge of pursuing the Lord's Resistance Army says many reports indicate its notorious leader Joseph Kony is seriously ill and on the run along the borders of Sudan's western Darfur region and the Central African Republic.

Francisco Madeira told reporters after briefing the U.N. Security Council on Wednesday that the nature of Kony's illness isn't known.

He said Central African Republic President Michel Djotodia, a former rebel leader, told him that he and "his people" have been in contact with Kony, and "they want to encourage him to surrender."

Madeira said "a good number" of Kony's followers are defecting because of pressure from African troops supported by U.S. military advisers.

The LRA is notorious for kidnapping thousands of children to be soldiers and sex slaves.