Complex sentence: Several hundred of Chechen rebel fighters and civilians and more than 50 Russian servicemen were killed in the course of more than two weeks of the siege and fighting that resulted in the destruction of the bulk of forces of the Chechen rebel field commander Ruslan Gelayev.
Split into simpler sentences: Several hundred of Chechen rebel fighters and civilians and more than 50 Russian servicemen were killed in the course of more than two weeks of the siege. The fighting resulted in the destruction of the bulk of forces of the Chechen rebel field commander Ruslan Gelayev.