Complex sentence: The target of the Indian operation was the Atgram complex, comprised of a Pakistani border outost on river Surma, a Masjid close to the outpost and the village of Atgram itself.
Split into simpler sentences: The target of the Indian operation was the Atgram complex. The complex itself comprised of a Pakistani border outpost on the River Surma, a Masjid close to the outpost and the village of Atgram itself.