By Louis Charbonneau

UNITED NATIONS (Reuters) - Two months of violence in Kenya have split the country along ethnic lines and there is a risk of further clashes if the political crisis is not resolved quickly, a top U.N. official said on Monday.

Exhausted by a post-election crisis that has killed more than 1,000 people, most of the 36 million Kenyans want a quick political deal between President Mwai Kibaki and opposition leader Raila Odinga so the country can get back to normal.

"The ethnic basis of much of what has happened was tragically clear," under-secretary-general for humanitarian affairs John Holmes told the U.N. Security Council about a recent trip he made to Kenya.

"Heightened ethnic awareness and fears have quickly spread through much of Kenyan society, fueling polarization," he said. "The effects of ethnic divisions on basic government services have, for example, been dramatic in some areas because staff have quietly left or fear to go to work."

He said it was obvious that the crisis in Kenya would not disappear even if a political agreement was reached in the coming days.

"It was clear that the people who have been displaced by this crisis in many cases will not be able to go home quickly," Holmes told reporters after the council meeting. He said the United Nations estimated that there were some 270,000 people still displaced as a result of the violence.

Teams for Kibaki and Odinga have agreed in principle to create a new prime minister's post for the opposition, which accuses the government of stealing the vote by fraud.

But the talks, mediated by former U.N. chief Kofi Annan, reached a standstill on Monday. The two sides are split on the premier's powers, sharing of ministries and the possibility of a new election if the coalition collapses.

SWIFT POLITICAL DEAL NEEDED

What began as a dispute over the vote count from the Dec. 27 election quickly descended into violent protests and ethnic fighting that were the east African nation's darkest moments since independence from Britain in 1963.

While a power-sharing agreement would likely not end all aspects of the crisis, failure to get one soon could be disastrous for Kenya, Holmes said.

"If there is no quick resolution to the political crisis, the risk of a fresh surge in violence, more displacement (of people) and further polarization of society is very high," he told the Security Council.

"The humanitarian consequences of this could dwarf anything we have seen so far," he said, adding later to reporters that "We are doing our contingency planning for that."

He said the roots of the crisis went deep and any long-term resolution would have to deal with them.

"Decades-long grievances over land, poverty, and wide economic inequalities must be addressed, in a context of strong population growth and limited availability of fertile land," Holmes told the council.

"Political manipulation of land and tribal issues will have to be prevented in future, including, no doubt, through constitutional and electoral reform to encourage more equitable representation of different interests in government."

He said the United Nations expected to remain actively involved in dealing with the humanitarian situation created by the Kenyan crisis for at least a year.