A Myanmar Buddhist monk and a Sri Lankan ultranationalist both known for campaigning against Muslims have formally signed an agreement to work together to protect Buddhism.

Ashin Wirathu leads the fundamentalist 969 movement that has been accused of instigating deadly violence against minority Muslims in Myanmar. He was a special invitee Sunday at a rally of Bodu Bala Sena, or Buddhist Power Force, which claims minority Muslims are trying to take over Sri Lanka by having more children, marrying Buddhist women and taking over businesses.

Wirathu signed the agreement with Bodu Bala Sena in Colombo on Tuesday after saying at the rally they would join forces. The groups said their agreement involves networking and building the capacity to stabilize Buddhism. They promised to release the contents of the agreement soon.