JAMMU, India (REUTERS) - India accused Pakistan of sending troops across the line dividing the disputed region of Kashmir on Tuesday, and said two of its soldiers were killed and one was wounded in a half-hour gunfight.

One military official told India's Times Now news channel that the body of one of the slain soldiers was later found mutilated in a forested area of the Himalayan territory.

A Pakistani army spokesman denied what it said were Indian allegations of "unprovoked firing" across the heavily militarised Line of Control (LoC) between the nuclear-armed neighbours.

The incident came two days after a clash along the LoC in which Pakistan said one of its soldiers was killed after an Indian incursion. India denied its troops crossed the line.

India and Pakistan have fought three wars since their independence in 1947, two of them over Kashmir.

Rajesh K. Kalia, spokesman for the Indian army's Northern Command, said Tuesday's "intrusion" was "a significant escalation ... of ceasefire violations and infiltration attempts supported by Pakistan Army".

"Pakistan army troops, having taken advantage of thick fog and mist in the forested area, were moving towards their own posts when an alert area domination patrol spotted and engaged the intruders," he said.

"The firefight between Pakistan and our own troops continued for approximately half an hour, after which the intruders retreated back towards their side of Line of Control."

In 1999, Pakistan-backed Islamist infiltrators occupied the Kargil heights in northern Indian Kashmir, with India losing hundreds of troops before reoccupying the mountains after bitter fighting that almost triggered a fourth war.

Indian military officials said the frequency of cross-border clashes has increased in recent weeks, with at least half a dozen ceasefire violations over the past week alone.

Firing and small skirmishes between the two countries are common along the LoC despite gradually improving ties in recent years.