Talks to end post-election violence in Kenya have been suspended, former UN head and mediator Kofi Annan has said.
In Nairobi, residents have expressed their desire for peace
Mr Annan said that negotiations had become acrimonious and that the situation had become "very dangerous".
He also said he would speak to President Mwai Kibaki and opposition leader Raila Odinga to find a way to move forward "much faster".
At least 1,500 people have been killed in ethnic and political violence since the disputed election, police say.
Mr Kibaki claimed victory in the 27 December election, but Mr Odinga said the poll was rigged.
The government and opposition are stalled on securing a power-sharing deal.
The opposition has threatened to stage protests across Kenya from Thursday if no deal is reached.
On Tuesday, the government said it was surprised that the talks had been suspended.
But a senior aide to Mr Annan suggested that government intransigence was to blame, the BBC's Adam Mynott reports from Nairobi.
"The talks have not broken down," Mr Annan said.
"But I am taking steps to make sure we accelerate the process and give peace to the people as soon as possible.
"The leaders have to assume their responsibilities and become directly engaged in these talks."
Earlier, Mr Annan had appealed to the leaders to help move the negotiations forward.
Both sides had agreed last week to create the post of prime minister, which would be taken by Mr Odinga, leading to hopes of a final deal soon.
However, they still needed to finalise which powers he would have.
The government now says the president should appoint the prime minister, which would not be an executive post.
As well as how to divide powers between a prime minister and a president, the rivals are also split on sharing cabinet positions and the possibility of a new election if the coalition collapses.
US, EU warnings
In Brussels, EU aid commissioner Louis Michel expressed "strong concern" and warned of consequences for any wreckers of the talks.
"The EU is determined to take all appropriate measures and all options are being considered," he said.
During a trip to China, US Secretary of State Condoleezza Rice criticised Kenyan parties for their lack of progress, saying she was disappointed by the "failure of leadership".
Talks on power-sharing have been dragging on for weeks
"The future of our relationship with both sides and their legitimacy hinges on their cooperation to achieve this political solution," she said.
"We will draw our own conclusions about who is responsible for lack of progress and take necessary steps."
Ms Rice visited Kenya last week in an effort to help broker a deal.
In Nairobi, government officials blamed the situation on false reports of deals reached during negotiations.
"We feel we are just being pushed and pushed and this is not fair," said government representative Mutula Kilonzo.
He said that he was confident there would be an agreement, but took issue with the statement issued by Ms Rice.
"This is a Kenyan issue and a Kenyan solution will be the one needed," Mr Kilonzo said.
Justice Minister Martha Karua said the dispute was over whether to entrench a power-sharing agreement in the constitution or just make statutory amendments.
But Musalia Mudavadi of Mr Odinga's Orange Democratic Movement said that from the beginning both parties had agreed that constitutional and legal amendments might be needed.
Tanzanian President and African Union head Jakaya Kikwete has now arrived in Nairobi to try to salvage the talks.