The UN Security Council says it is ready to take "further steps" which could mean new sanctions if Yemen's Shiite rebels don't immediately return to UN-led negotiations on a democratic transition.
The council expressed "grave concern" in a statement Friday at the announcement that the Houthi rebels were taking over the impoverished Arab nation and dissolving parliament.
Council members called on the Houthis "in the strongest terms" to abide by agreements providing for a Yemeni-led democratic transition.
The council called for the immediate release from house arrest of Yemen's president, prime minister and Cabinet members.
The statement reaffirmed the council's commitment to Yemen's sovereignty and territorial integrity.
Britain's UN Ambassador Mark Lyall Grant expressed hope that the council's strong message "will be listened to by everyone in Yemen."