Commotion broke out on Thursday at the venue of a rally in Gaya, shortly before Bharatiya Janata Party prime ministerial candidate Narendra Modi was to address it, prompting the police to resort to a lathicharge.
The police action to restore order came after the crowd at the rally in Gandhi Maidan, who had gathered for several hours, became restive, during which wooden barricades were also broken.
A section of the crowd also barged into the media enclosure.
The people at the rally ran helter skelter and flung chappals as policemen wielded lathis to control the crowd.
Police reinforcements were also rushed in.
The rally continued after BJP leaders appealed for calm.
Modi had addressed a rally at Gumla in Jharkhand earlier in the day.
A tight security cover was thrown here after Maoists blew up two mobile towers earlier in the day, exploding powerful bombs in two areas of Gaya district.
About 100 Maoists gathered in the areas and blew up two mobile towers of a private company by exploding powerful bombs at Manjhauli and Dumaria Bazar villages late last night, Gaya Superintendent of Police Nishant Tewari said.
The ultras have called a bandh in the Maoist-hit districts of south central part of the state in protest against the killing of ten of their cadres in Chhatra recently.
"We have anticipated all types of threats from the Maoists and terrorists. Security arrangements are being made accordingly," Director General of Police (DGP) Abhayanand said yesterday.