The president of Yemen has resigned along with his prime minister as Shia Houthi rebels tighten their grip on the capital Sanaa.
President Abdrabbuh Mansour Hadi and Prime Minister Khaled Baha tendered their resignations to parliament which reportedly refused to accept them.
The move came despite a deal to make political concessions to the rebels.
Rebel figures welcomed the news with one reportedly proposing the creation of a ruling presidential council.
The council would include Houthi-led groups, Abu al-Malek Yousef al-Fishi was quoted as saying by Reuters news agency.
Houthi leaders had previously committed themselves to withdrawing from key positions around the presidential palace and the home of President Hadi.
The US, which is helping fight al-Qaeda militants in Yemen, said it was still assessing the implications of President Hadi's move.
'Political maze'
In his letter of resignation, seen by the Associated Press news agency, Mr Hadi said the parties had reached a "deadlock".
"We found out that we are unable to achieve the goal, for which we bear a lot of pain and disappointment," he said.
A government source told the BBC ministers were resigning in protest at the rebels' challenge to Yemen's sovereignty and their seizure of state institutions.
In his resignation letter, Prime Minister Baha said the cabinet did not want to be dragged into an "unconstructive political maze".
Earlier this week, Houthi gunmen fired on Mr Baha's convoy and then laid siege to the presidential palace, where he was staying.
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Analysis: Sebastian Usher, BBC World Service
The resignation of the Yemeni president and his government is likely to plunge an already unstable country into uncharted territory.
It comes just a day after a deal was announced between the president and the Houthi rebels that was meant to paper over the sharpest edges of the current crisis.
The rebels received the concessions they demanded. For their part, they were meant to withdraw from the presidential palace and from Mr Hadi's own house, as well as releasing a presidential aide they abducted last week.
They have done none of this. Mr Hadi and his government say they cannot continue under such conditions. Yemen was already close to chaos - now it seems it has no president and no government.
Then on Wednesday the home of President Hadi was shelled, shattering a ceasefire that had been agreed only hours earlier.
The ceasefire deal had met a series of rebel demands including the expansion of Houthi representation in parliament and state institution.
In return, the rebels said they would pull back from their positions and free the president's chief of staff, whom they have held since Saturday. But so far they have not done so.
The Houthis, who follow a branch of Shia Islam known as Zaidism, have staged periodic uprisings since 2004 in an effort to win greater autonomy for their northern heartland of Saada province.
Since July the rebels have inflicted defeats on tribal and militia groups backed by the leading Sunni Islamist party, Islah, and battled al-Qaeda as they have pushed into central and western provinces.
President Abdrabbuh Mansour Hadi and Prime Minister Khaled Baha tendered their resignations to parliament which reportedly refused to accept them.
The move came despite a deal to make political concessions to the rebels.
Rebel figures welcomed the news with one reportedly proposing the creation of a ruling presidential council.
The council would include Houthi-led groups, Abu al-Malek Yousef al-Fishi was quoted as saying by Reuters news agency.
Houthi leaders had previously committed themselves to withdrawing from key positions around the presidential palace and the home of President Hadi.
The US, which is helping fight al-Qaeda militants in Yemen, said it was still assessing the implications of President Hadi's move.
'Political maze'
In his letter of resignation, seen by the Associated Press news agency, Mr Hadi said the parties had reached a "deadlock".
"We found out that we are unable to achieve the goal, for which we bear a lot of pain and disappointment," he said.
A government source told the BBC ministers were resigning in protest at the rebels' challenge to Yemen's sovereignty and their seizure of state institutions.
In his resignation letter, Prime Minister Baha said the cabinet did not want to be dragged into an "unconstructive political maze".
Earlier this week, Houthi gunmen fired on Mr Baha's convoy and then laid siege to the presidential palace, where he was staying.
line
Analysis: Sebastian Usher, BBC World Service
The resignation of the Yemeni president and his government is likely to plunge an already unstable country into uncharted territory.
It comes just a day after a deal was announced between the president and the Houthi rebels that was meant to paper over the sharpest edges of the current crisis.
The rebels received the concessions they demanded. For their part, they were meant to withdraw from the presidential palace and from Mr Hadi's own house, as well as releasing a presidential aide they abducted last week.
They have done none of this. Mr Hadi and his government say they cannot continue under such conditions. Yemen was already close to chaos - now it seems it has no president and no government.
Then on Wednesday the home of President Hadi was shelled, shattering a ceasefire that had been agreed only hours earlier.
The ceasefire deal had met a series of rebel demands including the expansion of Houthi representation in parliament and state institution.
In return, the rebels said they would pull back from their positions and free the president's chief of staff, whom they have held since Saturday. But so far they have not done so.
The Houthis, who follow a branch of Shia Islam known as Zaidism, have staged periodic uprisings since 2004 in an effort to win greater autonomy for their northern heartland of Saada province.
Since July the rebels have inflicted defeats on tribal and militia groups backed by the leading Sunni Islamist party, Islah, and battled al-Qaeda as they have pushed into central and western provinces.
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