Warplanes from a Saudi-led coalition hit the Houthi-controlled Red Sea port of Hodeida on Tuesday, destroying cranes and warehouses in the main entry point for aid supplies to Yemen's north.

Rival factions also battled further south overnight in Yemen's third city, Taiz, Arab television stations reported, as local militias opposed to the Houthis attempted to consolidate recent advances on it.

The human rights group Amnesty International meanwhile said the Saudi-led air campaign had left a "bloody trail of civilian death" which could amount to war crimes.

An Amnesty report said it had investigated eight coalition air strikes in Yemen that killed 141 civilians, including children.

Evidence revealed a pattern of strikes against populated areas, in most of which no military target could be located nearby, it said.

Coalition officials could not immediately be reached for comment on the Amnesty report but has previously denied targeting civilians. Amnesty also said it had investigated 30 attacks in Aden and Taiz by the Houthis that killed 68 civilians and also may amount to war crimes.

The Iranian-allied Houthis seized Yemen's capital Sanaa last September in what they called a revolution against a corrupt government, then took over much of the country.

The Saudi-backed President Abd-Rabbu Mansour Hadi fled to the southern port of Aden, then escaped to Riyadh in March. Gulf Arab countries led by Saudi Arabia intervened in the conflict to push back what they see as spreading Iranian influence in their backyard.