Complex sentence: The National Oppression demanded the release of their communist leader Badruddin Bahes, which the Afghan government denied holding and refused categorically to negotiate with the militants, in spite of the U.S. embassy's demands.
Split into simpler sentences: The National Oppression demanded the release of their communist leader Badruddin Bahes, whom the Afghan government denied holding. The government refused categorically to negotiate with the militants, in spite of the U.S. embassy's demands.