A policeman was critically injured after alleged cattle smugglers opened fire on him in Bihar's Samastipur district, a senior official said on Tuesday.

Acting on a tip-off, a team led by Assistant Sub-Inspector Nandkishore Yadav, the in-charge of Mohanpur police outpost, intercepted a truck illegally transporting cattle and arrested three alleged smugglers, Samastipur Superintendent of Police Vinay Tiwary said.