NEW DELHI — India and Pakistan exchanged fire across the line dividing the disputed Himalayan region of Kashmir on Saturday and Sunday, killing nine civilians and soldiers, according to authorities in both countries.

It was one of the deadliest sequences this year at the Line of Control, the highly militarized frontier where soldiers from the two countries regularly trade small-arms and artillery fire.

The barrage came amid increased tension between the nuclear-armed rivals.

India accuses Pakistan of stoking a three-decade insurgency against Indian rule in Kashmir by sending fighters and arms across the Line of Control. Pakistan denies the accusations.

Five civilians and one soldier were killed on Pakistan’s side of the Line of Control, a spokesman for the Pakistani army said Sunday. Two Indian soldiers and one civilian were also killed, a spokesman for the Indian Defense Ministry said.

India and Pakistan claimed to have killed larger numbers of the other country’s soldiers in the incident, but such assertions could not be verified independently. 

Gen. Bipin Rawat of the Indian Army told reporters that the exchange began when militants attempted to cross into Indian-controlled territory. Pakistan rejected the accusation and said India’s firing was “indiscriminate and unprovoked.”

The two countries reached a cease-fire agreement in 2003, and for several years, relative calm prevailed on the de facto frontier in Kashmir. Since 2014, however, cease-fire violations have jumped.