A state of alert has been sounded across India after a car bomb exploded near the Red Fort in Delhi, India, killing at least eight people and injuring many more.

The BBC has learned that at least 30 injured people are being treated at the nearest hospital to the scene.

Delhi Police spokesman Sanjay Tyagi told the BBC that the explosion took place in a Hyundai i20 car. There were three people in the car.

Witnesses said the explosion was so powerful that they were stunned for a few moments. One person even said the explosion shook the windows of his house.

A shop owner some distance from the scene said he fell three times after the explosion, then managed to pull himself together.

Union Home Minister Amit Shah visited the site of the incident last night. Many leaders from home and abroad, including President Droupadi Murmu, Prime Minister Narendra Modi and Opposition Leader Rahul Gandhi, have issued statements.

In major cities like Kolkata and Mumbai, additional police forces have been conducting special search operations on the streets since night. Extra vigilance has also been issued at Indian airports.

The US Embassy in Delhi has issued an alert following the blasts, advising US citizens to avoid the Red Fort and Chandni Chowk areas.

Meanwhile, Jammu and Kashmir Police claimed that they have recovered around 3,000 kg of explosives, various chemicals used to make blasts, four pistols and guns during searches in Uttar Pradesh and Haryana. Seven people, including two doctors, have been arrested - who police claim are associated with two organisations - Jaish-e-Muhammad and Ansar Ghazwatul Hind.

However, the arrest has no connection with the Delhi blasts.

Indian Home Minister Amit Shah visited the blast site and the hospital where the injured were being treated that night. He later briefed Prime Minister Narendra Modi on the details.

Amit Shah said that elite commando forces – the National Security Guard and the anti-terrorism agency – the National Investigation Agency have been deployed to investigate the blast.

In his words, we are looking into all aspects - a detailed investigation will be conducted. The investigation will be completed quickly and the results will be brought before the general public.

Members of the Uttar Pradesh Anti-Terrorism Squad, National Security Guard and Central Reserve Police Force are at the scene.

Videos and pictures from the scene show mangled bodies strewn across the road. Delhi's Deputy Chief Fire Officer AK Malik said, "We quickly reached the spot and started work to control the fire. The fire was brought under control at around 7:29 pm."

A large number of police and security personnel have been deployed in and around the Red Fort following the blast. The blast has sparked widespread panic near one of India's most popular tourist attractions, which is packed with tourists throughout the year.