Complex sentence: In 1996-1998, Yatom was head of the Mossad security service, between 1999 and 2001 he served as Prime Minister Ehud Barak's Chief Of Staff and security advisor.
Split into simpler sentences: In 1996-1998, Yatom was head of the Mossad security service. Between 1999 and 2001 he served as Prime Minister Ehud Barak's Chief Of Staff and security advisor.