Ahead of the two-day bandh called by Naxals to protest the killing of their leader Azad, the Central government today asked Maoist-affected states to remain vigilant and take precautionary measures to foil any attempt of violence by the ultras.

The Home Ministry asked the Naxal-affected states and Indian Railways to take all possible steps to guard railway properties, tracks, public places, markets and other vital installations to avoid any untoward incident during the 48-hour bandh called by the CPI (Maoists) beginning tomorrow.

The bandh was called in protest against the killing of top Naxal leader Cherukuri Rajkumar alias Azad in Andhra Pradesh last week.

The Maoists have vowed to take revenge of Azad's killing by the Andhra Pradesh Police in an alleged encounter near Sarkapalli village in Adilabad district. The Maoists also reportedly asked people not to travel by train during the bandh period.

The Centre is particularly concerned over the safety of Shatabdi and Rajdhani Express trains, rail tracks and passengers as nearly 150 people lost their lives following the derailment of Jnaneswari Express in West Bengal on May 29 by Maoists.

Meanwhile, the Railways have said it was taking the situation seriously and has kept 'crack teams' on standby.

Pilot trains will run during the day time also in Naxal-affected areas and all trains will run in bunches.