Complex sentence: From 15 May, hundreds of rebels started departing the city in stolen vehicles, leaving only 500 men led by Cubans, mostly were garrisoned in the quarter of Manika and in the suburbs.
Split into simpler sentences: From 15 May, hundreds of rebels started departing the city in stolen vehicles, leaving merely 500 men led by Cubans. Most were garrisoned in the quarter of Manika and in the suburbs.