Thousands of people have rallied across Yemen denouncing a move by Houthi fighters to dissolve parliament and form their own government, calling the decision a coup.
Protesters staged demonstrations in several cities on Saturday, a day after the Houthis announced the formation of a "security commission" to govern the country for the next two two years.
Demonstrations erupted in the capital Sanaa; as well as the cities of Aden, Hodeida, Taiz, Dhamar, Ibb and al-Bayda.
Sources told Al Jazeera that at least 17 people were arrested at the Sanaa rally, after the Houthis reportedly fired live ammunition to disperse crowds.
In Taiz, Yemen's third-largest city, protest tents were pitched outside a local government building against what anti-Houthi demonstrators called a "coup d'etat", residents said.
Protests also erupted in the western city of Hodeida and in Aden, Yemen's second city in the south where the governor, Abdel Aziz bin Habtur, called the Houthi declaration "a plot against the constitution".
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The Houthis, which have controlled the capital since September last year, said they would set up a 551-member national council to replace the dissolved parliament.
The Shia movement said a five-member presidential council would form a transitional government to run the country for the next two years.
Al Jazeera's Jamal Elshayyal, reporting from Aden, said the announcement threatened to split an already divided country and would have ramifications throughout the region.
"Popularly speaking the Houthis are a Shia minority, and there is a lot of opposition to them from the Sunni majority," he said.
"Politically speaking you have regions like Aden that have said they reject the Houthi takeover and will not accept orders from Sanaa. Some have called for like-minded governorates to come together and discuss the situation.
"This is an opportunity for them to advance their cause and increase calls for separation."
Yemen's south accounts for 70 percent of the country's production and groups in the region have been demanding a return to the full independence the south enjoyed from 1967 to 1990.
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The Houthi takeover has drawn a strong rebuke from Washington, the United Nations and neighbouring Gulf states.
On Saturday, the six-nation Gulf Cooperation Council (GCC) said the Houthi "coup" endangered the "territorial integrity of Yemen."
"The Houthi coup marks a grave and inacceptable escalation... and endangers the security, stability, sovereignty and territorial integrity of Yemen," it said in a statement.
A senior American official, speaking in Munich after Secretary of State John Kerry met leaders of Yemen's Gulf neighbours, said the US and the Gulf Cooperation Council "don't agree" with the Houthi "presidential council", while the UN Security Council raised the prospect of possible sanctions.
Meanwhile, in the oil-rich province of Maarib, a spokesman for the influential Sunni tribes told the AFP news agency they had "rejected" the coup.
Yemeni female Nobel Peace Prize laureate Tawakkol Karman said the declaration was "null and void" and expected the people to rise against the Houthi "coup", and "liberate" the capital.
The fall of President Abd-Rabbu Mansour Hadi's Western-backed government raises fears of chaos engulfing Yemen, strategically located next to oil giant Saudi Arabia and on the key shipping route from the Suez Canal to the Gulf.
Source: Al Jazeera and agencies