A group of Shamans from Peru on Monday performed a ritual to plead for good relations between Colombia and Peru, after a diplomatic spat over the ownership of a recently surfaced island in the Amazon.

The ceremony, held atop San Cristobal Hill, was led by Marino de los Santos, who described the site as an Apu, or “mountain of power.” The 27-square-kilometre territory, home to about 3,000 people ...