Indian police are investigating if there is a link between this week’s car blast in Delhi and the earlier arrest of a group of seven men from the restive Kashmir region with arms and bomb-making material, three sources familiar with the probe said on Wednesday.

The blast on Monday evening outside Delhi’s historic Red Fort killed eight people and wounded at least 20, the first such explosion in the heavily guarded city of more than 30 million people since 2011.

Indian authorities are investigating the blast under a stringent anti-terrorism law and have said that all angles are being probed. They have not named anyone or made any arrests in connection with the explosion.

TWO DOCTORS ARRESTED

Hours before the blast in Delhi, police in the Jammu and Kashmir federal territory said they had arrested seven men, including two doctors, in connection with a separate anti-terror probe and searches in Kashmir, and in the states of Haryana and Uttar Pradesh that border Delhi.

Police found two pistols, two assault rifles and 2,900 kg of bomb-making material during the raids, a Kashmir police statement said.

"The investigation has revealed a white collar terror ecosystem, involving radicalised professionals and students in contact with foreign handlers, operating from Pakistan and other countries," it said, adding that the men were linked to Pakistan-based militant groups Jaish-e-Mohammad and Ansar Ghazwat-ul-Hind.

Pakistan's foreign office did not immediately respond to a request for comment.

India accuses Pakistan of supporting Islamist militants in Kashmir, the Himalayan region which both nations claim, but Islamabad denies the accusation. Tens of thousands of people have been killed in the anti-Indian insurgency there since 1989 although violence has tapered off in recent years.

Senior Indian leaders including Prime Minister Narendra Modi have vowed to punish those behind the Delhi blast, with Modi saying no "conspirator" would be spared.

More bodies were retrieved on Tuesday after a boat carrying Myanmar's persecuted Rohingya Muslim minority sank,

In April, 26 men were killed in an attack on Hindu tourists in Kashmir which New Delhi blamed on what it called Islamist "terrorists" backed by Pakistan, a charge denied by Islamabad.

The crisis led to the worst military conflict between the nuclear-armed rivals in decades before they agreed to a ceasefire after four days.

RAIDS IN KASHMIR

The connection between the Delhi car driver and the seven men arrested is being investigated, the three sources said, speaking on condition of anonymity as they were not authorised to speak to the media on the sensitive issue.

Investigations were focused on whether the driver was a doctor and a colleague of one of the two arrested, one of the sources said.

Spokespersons for the Delhi Police and the National Investigation Agency - the federal anti-terror agency that has taken over the probe - did not respond to requests for comment.

Following the Delhi blast, Kashmir police carried out raids at hundreds of locations in the Himalayan region and about 500 people were detained, a Kashmir police source told Reuters. Most were let off after questioning, the source said.