A senior police officer, Superintendent of Police (Lucknow city) B.P. Ashok, was injured in the crossfire.

Gaurav Mishra, a Class 6 student of City Montessori School (CMS) here whose father runs a construction business in Delhi, was rescued. He had been kidnapped Wednesday by the four men, including the driver employed by his family.

"The four men were killed in the shootout that took place in Malihabad town in Lucknow," Deputy Inspector General of Police (DIG, Lucknow range) Prem Prakash told reporters here.

"The gun battle with the abductors, who were riding a car, continued for nearly an hour. Though we managed to shoot them dead, SP B.P. Ashok was injured."

After the kidnapping Wednesday, the abductors had made ransom calls at Gaurav's home, demanding Rs.1 crore for the release of the child.

Gaurav had been kidnapped by the driver Sushil Yadav, who went to pick him up after school with three aides, said Prakash.

The plot unravelled when police questioned the driver's family in Sitapur, abut 80 km from here.

"When our team reached Sitapur, we found none present there and therefore the driver came under our scanner," Prakash disclosed.

Thereafter, alerts were sounded to stop an Indica car that belonged to Gaurav's family.

The car was spotted in Malihabad town Thursday morning. Those inside the vehicle shot at the police team and were later shot dead in the cross firing.