* Kabila pressures UN to consider reducing peacekeepers
* Withdrawal will take at least two years - UN official
* Situation in eastern Congo remains very fragile

UNITED NATIONS (Reuters) - The United Nations is quietly preparing an exit strategy for its troops in the Democratic Republic of Congo, the biggest U.N. peacekeeping mission in the world, diplomats and officials said.

Speaking on condition of anonymity, diplomats and U.N. officials said President Joseph Kabila was putting pressure on the U.N. and Security Council ahead of the country's 50th anniversary next year to come up with a plan for ending the peacekeeping mission, known as MONUC.

MONUC has been in the former Belgian colony since 1999 to help the government of Congo as it struggles to reestablish state control over the vast central African nation following a 1998-2003 war and humanitarian disaster which have killed an estimated 5.4 million people.

"It's partly a question of dignity," one Western diplomat told Reuters. "Kabila's eager to show that his government's reliance on U.N. peacekeeping is decreasing. It's understandable. No leader wants to give the impression that he needs U.N. peacekeepers to stay in power."

Kabila, who won the country's first democratic election in four decades 2006, is expected to run for re-election in 2011.