"Armed naxalites opened fire when a cultural programme was on between 12.30 am and 1 am and killed 17 people, including Anup Marandi, the son of former Chief Minister Babulal Marandi," said Deputy Inspector General of police R K Mullick.

The injured were rushed to Giridih hospital, he said.

Condemning the attack, Jharkhand Chief Minister Madhu Koda said, "It is a sad incident, in which Anup Marandi was killed. Such attacks were in retaliation of police action against them. In last few months police has arrested a number of Naxals and destroyed their bunkers, training camps."

Koda said he had spoken to Marandi and would visit the village.

Marandi's brother Nunulal, who was also present at the function, escaped unhurt, police said here.

The naxals mingled with the crowd that had gathered at the cultural programme before they attacked, additional superintendent of police of Giridih Arun Kumar Singh said.

The programme was organised as part of a local football match that was held on Friday afternoon.

Singh admitted to lapses by the police in the shootout.

The in-charge of Deori police station, under which Chilkhadih falls, Virendra Singh was deputed along with police personnel for the football match and cultural programme.

But he returned in the evening itself after prize distribution without waiting till the end. "It is a clear case of negligence on the police officer's part," Singh said.

The attackers could have sneaked back to Bihar as the village was on the border with that state, he said.

Jharkhand Director General of Police V D Ram has rushed to the spot and an intensive search and combing operation has been launched by both Jharkhand and Bihar police.

Marandi said he had received the information that his son was among those killed in the incident, in which according to information received by him some attackers were in CRPF uniform.

"My family is a target of naxalites. My son and brother should not have ventured out at night," he said.

He alleged that there was an increase in Maoist violence in Jharkhand and said the Chilkhadih incident was another "episode of a series of Maoist attacks."

"Neither the Jharkhand government not the Centre has any policy to curb naxals or bring them to the mainstream. The naxals have spread their tentacles in all districts of the state and 156 districts in the country," Marandi, who represents Koderma Lok Sabha constituency and heads Jharkhand Vikas Morcha (Democratic) said.