CAIRO (AP) — An international rights group says Yemen's warring parties are obstructing crucial aid to the Red Sea port of Hodeida endangering millions in what is already the world's worst humanitarian crisis.

Thursday's report by Amnesty International blamed the Iran-backed Houthi rebels' "excessive and arbitrary bureaucratic procedures" for restricting the movement of humanitarian workers in Hodeida. Citing aid workers, it said the rebels exert influence over who receives aid and in which areas.

Amnesty also blamed the Saudi-led coalition battling the Houthi rebels for its "excessive" inspection and restriction of essential aid deliveries. It said the coalition's recent offensive in Hodeida is cutting off a crucial supply line, which "would further deepen" the crisis.

Impoverished Yemen has been devastated and pushed to the brink of famine by a stalemated three-year civil war.