NEW DELHI, June 13 (Xinhua) -- At least 64 children have died due to encephalitis in India's eastern state of Bihar, local media reported Thursday.

The deaths have taken place in the past 12 days, according to India's state-run broadcaster All India Radio (AIR).

"The casualties have been reported from Muzaffarpur Samastipur and Vaishali districts, with Muzaffarpur recording the highest number of casualties," the AIR said.

According to officials dozens of children are undergoing treatment in Sri Krishna Medical College Hospital and Kejriwal Hospital in Muzaffarpur, where the condition of some was stated to be critical.

On Wednesday a multi-specialist high-level team from India's federal health ministry visited Muzaffarpur to assist the local government in the containment and management of rising cases of Acute Encephalitis Syndrome (AES).

Experts said the disease mostly affects children below 15 years of age and symptoms of AES are acute-onset of fever and a change in mental status -- confusion, disorientation, delirium, or coma -- and the onset of seizures.

According to officials, AES outbreaks are routine in areas in and around Muzaffarpur during summer.

Bihar Chief Minister Nitish Kumar said the AES cases recurred because awareness campaign was not done properly.