Police in Paris canceled a June 20 protest by the NCRI Iranian opposition following a warning from security services of a heightened threat from rival monarchist activists. 

Past NCRI rallies, organized by the political arm of the People's Mujahideen ​Organisation of Iran (PMOI), which people from around the world come to attend, have passed without incident, Reuters reported. 

The intelligence assessment pointed to growing tension between the PMOI and Iranian monarchists who are backing Reza Pahlavi, who is the exiled son of the toppled shah. Both groups are in a rivalry to be the sole legitimate Iranian opposition. 

The protest was canceled hours before it was to begin.