In a shocking incident that left disciples of an ashram aghast, two nuns were brutally killed and another monk sustained multiple injuries on Wednesday by an unidentified assailant at a mission in the northern fringe of Kolkata, police said on Thursday.

“At around 9:30 pm, a man tried to force his way into the mission with a sword. On being refused entry, he attacked the nuns and monks. The head of the mission Sangeeta Devi and another nun named Dulu Datta were killed on the spot after their throats were slit,” a police official said.

A monk identified as Anandakamal Brahmachari who tried to thwart attacks on nuns, had been admitted to hospital in a critical condition after the assailant hit him with a sword. However, police are to yet to find out how the attacker suffered the injuries.