NEW DELHI (REUTERS) - India's National Investigation Agency (NIA) charged 19 people, including seven Pakistani nationals, on Tuesday (Aug 25) over a deadly bomb attack on a security convoy in the Indian-controlled part of Kashmir last year.

The bombing on Feb 14, 2019, killed 40 paramilitary policemen, leading to aerial clashes between India and Pakistan, two long-time, nuclear-armed rivals.

Pakistan-based militant group Jaish-e-Mohammad claimed responsibility for the attack.

On Monday, the NIA said four of the seven Pakistani nationals charged in the attack were at large, while the other three had been killed in separate clashes with security forces.

"The charge sheet has brought on record the all-out involvement of Pakistan-based entities (in) carry(ing) out terrorist strikes in India and to incite and provoke Kashmiri youth," an NIA statement said.

The other 12 accused are local residents of Indian Kashmir, some of whom have been killed in clashes, some arrested, and the rest missing.

One of the accused, a 20-year-old man from Kashmir's capital city Srinagar, ordered four kilograms of aluminium powder on Amazon to help his accomplices make explosives used in the attack, according to the NIA.

India has long accused Pakistan of harbouring militants and supporting an insurgency in Muslim-majority Kashmir, a Himalayan region split between the two countries but claimed in full by both.

Pakistan has denied the accusations.

Two of the three wars between India and Pakistan have been fought over Kashmir.

Indian Prime Minister Narendra Modi's nationalist government tightened its grip on Kashmir last August when it stripped away its special status that allowed it to make some of its own laws.

The decision, the most far-reaching political move in one of the world's most militarised regions in nearly seven decades, polarised opinion, with Kashmiri leaders calling it aggression against the state's people.