Yemen’s Houthi movement, which has seized the capital Sanaa, rejected a UN call to cede power on Monday, stoking tensions after Yemen's Gulf neighbors 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 group overran the capital in September.

The UN Security Council, in a resolution adopted unanimously on Sunday, urged the Houthis to relinquish power, release President Abed-Rabbo Mansour Hadi along with other officials, and to negotiate in "good faith."

In response on Monday, the Houthis 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 criminalize meddling in internal affairs."

The statement from the "Supreme Revolutionary Committee" — a new entity established after the Houthis dissolved parliament — was referring to the neighboring 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 Houthis ousted the government and dissolved parliament, tightening their grip after Western-backed Hadi offered to resign in protest at their advance.

Prime Minister Khaled Bahah tendered his resignation at the same time, and both have been held under effective house arrest by the Houthis ever since.

Envoy seeks Hadi release

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,” 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 on Sunday, the UN Security Council demanded the Houthis "immediately and unconditionally" engage in UN-brokered negotiations and withdraw their forces from government institutions.

It also demanded the militia release Hadi, Bahah and other officials and activists under de facto house arrest or in detention.

Several large anti-Houthi demonstrations have been carried out in Sanaa and the southern city of Aden since the Houthis ousted Baha’s government.

On Sunday, Houthis announced a ban on all demonstrations against them unless they are authorized by the interior ministry, which itself is now under their control.

Meanwhile, the family of demonstrator Saleh Awadh al-Bashiri, detained by the Houthis on Wednesday at a protest against their takeover, said he had died of torture wounds suffered in captivity.

Another two protesters who were held with him have been hospitalized after being found wounded and left on a street.

Amnesty International accused the Houthis on Monday of torturing protesters "in a bid to dissuade dissent."

"The Houthi 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 protesters have been detained and tortured for days on end. The safety of all those who dare to speak out against the Houthi rule is on the line," she said in a statement.