Unidentified assailants on Tuesday shot dead a Samajwadi Party leader in broad day light near the party office in Mau triggering protests by the party workers.
The victim Amar Nath Yadav, who was the district president of the SP student wing, was sprayed with bullet while he was coming out of the party office in Bal Niketan Tiraha area on Tuesday morning, police said.
Yadav died on the spot, police said adding that the borders of the town had been sealed and a massive manhunt had been launched to nab the culprits.
The killing of Yadav triggered strong protests from the SP workers, who led by the party MP Chandradeo Rajbhar, blocked traffic on the main road and also indulged in stone pelting.
The police resorted to lathi charge to disperse the mob and forcibly took possession of the dead body.
The SP leader had a criminal past and old enmity could be the motive behind the killing, police added.
Some journalists covering the incident were also allegedly assaulted by the policemen, sources said that over six scribes suffered injuries and were admitted to the hospital.
Adequately security personnel had been deployed to maintain order, sources said adding that the situation was tense but under control.