Yemen's embattled president has reached a peace deal with Shia Houthi rebels occupying key points in the capital Sanaa, reports say.
President Abdrabbuh Mansour Hadi's office said major concessions had been offered to the rebels, who took over his palace and surrounded his home.
They will play a bigger political role while a new constitution they opposed may be amended, the office said.
The rebels are expected to release Mr Hadi's chief of staff in return.
There was no immediate confirmation of the deal from the rebels.
According to some accounts, the president has been a captive in his own home, BBC Middle East analyst Sebastian Usher says.
He remains nominally in charge but the Houthis are in control, our analyst adds.
The rebels have denied trying to carry out a coup against him but their leader, Abdul Malik al-Houthi, went on TV on Tuesday to accuse him and other Yemeni leaders of ignoring the people's interests.
The UN Security Council has backed Mr Hadi's authority as the legitimate president in a statement agreed by all 15 members.
The US stressed on Wednesday that he remained president and said a joint counter-terrorism operation against al-Qaeda in the Arabian Peninsula militants (AQAP) was continuing.
Point of no return'
Ahead of the announcement of the deal, land, sea and air crossings to the country were closed, local media reported.
The main security body in the southern port city of Aden said the measure was necessary because of the "dangerous developments in the capital".
The Houthis, also known as Ansar Allah (Partisans of God), are believed to have taken control of most media outlets. They are also thought to have besieged the residence of Prime Minister Khalid Bahah.
Analysis: Abdullah Ghorab, BBC Arabic, Sanaa
The current situation in Yemen has had a grave impact on people's lives, especially for residents of the capital. Hundreds of families have fled the capital to safer provinces.
There are also long queues at petrol stations, as a result of a nationwide fuel crisis that stems from security problems in the province of Maarib, east of Sanaa. It is the location of many oil and gas fields, as well as a major refinery and power plant. The instability there has led to the price of a cylinder of domestic gas rising from $6 to $24 in some rural areas.
Sanaa residents are also complaining about food price hikes, which have seen the cost of basic supplies increase by more than 30%.
The European Union's foreign policy chief warned on Tuesday that the situation was making Yemen's poorest people suffer the most.
The rebels said earlier that the president remained in his home and was free to leave but an aide told AP news agency Hadi could "not leave his house" because the Houthis had removed his guards and deployed their own fighters.
In his televised address on Tuesday, Mr Houthi repeated his demand for Mr Hadi to implement a peace deal signed when his men overran the capital in September.
Yemen had "sunk deep into corruption and tyranny" and was moving towards a "complete collapse", he warned.
Mr Houthi accused the government of encouraging the spread of AQAP, which has vowed to defend Yemen's Sunni community against the Houthis.
Mr Hadi's chief of staff, Ahmed Awad bin Mubarak, was abducted on Saturday.
The draft constitution is hoped to bring an end to years of instability and under-development.
The General People's Congress party of the former President, Ali Abdullah Saleh, has endorsed the rebels' demands.
Mr Saleh has long been suspected of backing the Houthis, even though he fought against them before being forced to step down after a popular uprising in 2011.
On Wednesday, the Qatari-based TV channel al-Jazeera broadcast what it said was a leaked conversation showing collusion between Mr Saleh and the Houthis.
The Houthis, who adhere to 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 AQAP as they have pushed into central and western provinces.
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