At least eight persons were killed in an explosion in a car parked near gate number one of the Red Fort metro station in Delhi on Monday, ANI quoted the medical superintendent of the Lok Nayak Jai Prakash Narayan Hospital as saying.

The cause of the explosion was not immediately clear.

“Fifteen people have been brought to Lok Nayak Hospital,” the official told the news agency. “Eight of them died before reaching the hospital. Three are seriously injured. One is in stable condition.”

Delhi Police Commissioner Satish Golcha told ANI that the explosion occurred at about 6.52 pm.

“A slow-moving vehicle stopped at the red light,” said Golcha. “An explosion happened in that vehicle, and due to the explosion, nearby vehicles were also damaged.”

The metro station is located near the Red Fort in the Old Delhi area, among the most popular tourist sites in the capital.

Union Home Minister Amit Shah told ANI said that the Delhi Police, the National Security Guard and the National Investigation Agency are investigating the matter and all possibilities were being taken into account.

Following the explosion, Uttar Pradesh was put on high alert, Amitabh Yash, the state assistant director general of police (law), told ANI.

He added that the director general of police had issued instructions to all senior officers in Uttar Pradesh to increase security at “sensitive religious sites, sensitive districts and border areas”.

“All security agencies have also been alerted,” said Yash. “Police in all districts of Uttar Pradesh have been put on alert. An order was issued from Lucknow to increase patrols and checks in sensitive areas.”