NEW DELHI — Communist rebels opened fire on a crowd of revelers at a festival in eastern India today, killing a politician’s son and 17 other people, police said.

About 25 Maoist guerrillas attacked the village festival in the remote state of Jharkhand, firing indiscriminately, a local police chief, Arun Kumar Singh, said.

Among the dead was Anuplal Marandi, the son of the state’s former chief minister, Babulal Marandi, he said. The politician was thought to be on the rebel’s hit list after leading a crackdown against them while in office, Mr. Singh said.

Some 14 people were killed in the attack and four others died later in a hospital. Three more people were wounded, he said. The rebels, who frequently target police and government officials, also threw a bomb into the crowd before fleeing.

Police have launched a manhunt and sealed the state’s borders, Mr. Singh said.

The rebels, also known as Naxalites after the Naxalbari region where the movement was born, are mainly active in six of India’s 28 states — Andhra Pradesh, Jharkhand, Bihar, Karnataka, Orissa, and Chattisgarh — where widespread poverty has fueled a lengthy insurgency by militants demanding land and jobs for agricultural laborers and the poor.

The movement claims inspiration from Chinese revolutionary Mao Zedong.

India’s recent economic boom has created immense wealth, but the prosperity has not reached most of its 1.1 billion people, two-thirds of whom are farmers. Many peasants have joined the insurgents in the demand for land and jobs.