Pope Francis and the grand imam of Southeast Asia’s largest mosque vowed Thursday to fight religiously inspired violence and protect the environment, issuing a joint call for interfaith friendship and common cause at the heart of Francis’ visit to Indonesia, the Associated Press reported.

In an encounter rich with symbolic meaning and personal touches, Francis travelled to Jakarta’s iconic Istiqlal Mosque for an interreligious gathering.

There, he and the grand imam, Nasaruddin Umar, stood at the ground-level entrance to the “Tunnel of Friendship,” an underpass which connects the mosque compound with the neighbouring Catholic cathedral, Our Lady of the Assumption.

Indonesia, which has the world’s largest Muslim population, has held out the tunnel as a tangible sign of its commitment to religious freedom, which is enshrined in the constitution.

Pope Francis travelled to Indonesia, at the start of an 11-day, four-nation trip to Asia and Oceania.