Mathura: The daylong Janmashtami celebrations began in Shri Krishna Janmasthan and other temples here this morning with Mangal Aarti, and thousands of devotees flocking to offer prayers.

Heavy security arrangements have been made with CRPF jawans, Black Cat commandos, PAC jawans and local police drawn from Agra, Kanpur and Jhansi ranges posted to keep strict vigil.