SRINAGAR (Reuters) - The Indian army said it had destroyed four Pakistani military posts on Saturday along its contested border, the latest escalation of tensions between the nuclear-armed neighbors.

The attack comes a day after India and Pakistan traded accusations that each had killed civilians in cross-border shelling in the Kashmir region, which is claimed in its entirety by both countries but controlled in part by each.

"Four Pak posts destroyed in massive fire assault in Keran Sector. Heavy casualties inflicted," the Indian army's Northern Command said in a statement on its Twitter account late on Saturday.

The Indian army gave no further details of the assault, but an officer, who asked that his name not be used, confirmed that troops on both sides had been exchanging mortar fire in and around an area known as the Keran sector since Saturday morning.

Pakistani military officials were not immediately available for comment on Saturday evening.

On Friday, a Pakistani official said three civilians were killed as Indian troops shelled villages along the Line of Control in Pakistan-administered Kashmir. Indian officials, meanwhile, said two civilians died when Pakistani shells hit India-administered Kashmir.

The Indian army on Friday said in a statement that militants at the border mutilated the body of an Indian soldier they had killed before crossing back into Pakistan.

The army had warned that the "act will invite an appropriate response", saying the militants were "supported by covering fire from Pakistan Army posts".

Shelling by both sides in the divided and disputed Himalayan regions has been going on since gunmen killed 19 Indian soldiers in September at an army camp in Kashmir, an attack India blamed on Pakistan-based militants.

(Reporting by Fayaz Bukhari with additional reporting by Drazen Jorgic in Islamabad; Writing by Aditya Kalra, editing by Tom Lasseter and Richard Balmforth)