A Shiite militia that has seized Sanaa defiantly rejected Monday a UN call to cede power, stoking tensions after Yemen's Gulf neighbours appealed to the Security Council to act forcefully.
Yemen is a traditional US ally in the fight against Al-Qaeda, but the impoverished Arabian Peninsula country has descended into chaos since the militia known as Huthis overran the capital in September.
The UN Security Council, in a resolution adopted unanimously on Sunday, urged the Huthis to relinquish power, release President Abedrabbo Mansour Hadi along with other officials, and to negotiate in "good faith".
It raised the possibility of sanctions, without going as far as Gulf Arab countries, which have demanded coercive measures under Chapter Seven of the UN Charter.
In response Monday, the Huthis told the powerful UN body to "respect the will and sovereignty of the Yemeni people, and to be accurate and objective".
They also told the Council "not to follow the lead of regional powers that aim tirelessly to eliminate the will of the Yemeni people in a flagrant violation of international conventions that criminalise meddling in internal affairs."
The statement from the "Supreme Revolutionary Committee" was referring to the neighbouring Gulf monarchies which had demanded tough UN action.
"The revolution does not target our brothers in the Gulf Cooperation Council; not now, nor in the future," said the statement.
On February 6, the Huthis ousted the government and dissolved parliament, tightening their grip after Western-backed President Hadi offered to resign in protest at their advance.
Prime Minister Khalid Bahah tendered his resignation at the same time, and both have been held under effective house arrest by the Huthis ever since.
- Envoy seeks Hadi release -
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On Monday, the UN envoy to Yemen, Jamal Benomar, vowed to press for their release, after he visited Hadi at his besieged house in Sanaa.
"I assured him that we will continue our efforts to lift the house arrest imposed on him and the Prime Minister" Khalid Bahah, Benomar said in a statement.
The information minister in Bahah's resigned government, Nadia Sakkaf, said meanwhile that Hadi needed to travel abroad "immediately" for medical treatment.
"I visited President Hadi today. He has a heart condition and was quite ill. He must be allowed to travel for treatment," Sakkaf wrote on Twitter.
In its resolution issued Sunday, the UN Security Council demanded the Huthis "immediately and unconditionally" engage in "good faith" in UN-brokered negotiations, withdraw their forces from government institutions and relinquish power.
It also demanded the militia release Hadi, Bahah and other officials and activists under de facto house arrest or in detention.
The Huthis overran Sanaa unopposed in September.
They have since expanded their control to coastal areas and regions south of Sanaa, where they have faced fierce resistance from Sunni tribes and Al-Qaeda militants.
Amnesty International accused the Huthis on Monday of torturing protesters "in a bid to dissuade dissent".
"The Huthi stooped to a dangerous new level of intimidation and violence to strike fear into anyone protesting their rule," said Donatella Rovera, senior crisis response adviser at Amnesty, currently in Yemen.
"Testimonies reveal how protestors have been detained and tortured for days on end. The safety of all those who dare to speak out against the Huthi rule is on the line," she said in a statement.