According to police, a group of armed men Sunday attacked the meet at a Christian missionary in Sasaram in Rohtas district, 200 km from here. They beat up people present there, tore down posters and burnt books and leaflets.
Complaints have been filed against nine Bajrang Dal activists.
The injured were immediately admitted to hospital.
Witness said that about 40 masked men attacked the Christian prayer meet and warned against holding similar weekly meetings, said K.K. Sharma, Deputy Superintendent of Police (Sasaram).
"The attackers shouted slogans against the conversion of Hindus to Christianity," he added.
Bajrang Dal leaders in the district were apparently unhappy over the missionary converting many Dalits. In the last two months, nearly 50 Dalit families have reportedly converted to Christianity.