Hundreds of supporters of Yemen's Houthi rebels took to the streets of the capital Sanaa on Wednesday to protest against the US labelling their movement as terrorists in one of the final acts of outgoing President Donald Trump.

"We've come out to say the United States is the mother of terrorism and doesn't have the right to classify anyone as terrorist," a demonstrator told AFP, hours before President-elect Joe Biden was to take over from Trump.

Hizam Al Assad, a member of the Houthis' political office, condemned "the continued aggression against the Yemeni people by US administrations".

Biden's pick for secretary of state, Antony Blinken, said on Tuesday the new administration would review the designation and also end support to the devastating Saudi offensive on the country.

Blinken said he would "immediately" review the labelling by the outgoing administration of the Iran-linked insurgents, fearing the move would worsen Yemen's humanitarian crisis.

Trump's administration announced the move on January 11, just nine days before Biden's takeover.

Trump was a staunch ally of Saudi Arabia, offering US logistical help and military sales for its six-year campaign to dislodge the rebels who have taken over much of neighbouring Yemen.

But the United Nations and aid groups have warned the terrorist designation risks worsening the plight of a country where millions depend on aid to survive.

The designation took effect on Tuesday, with the Houthis warning they would respond to any action against them.

"We are ready to take all necessary measures against any hostile act," they said in a statement.