UNITED NATIONS (AP) — Liberia is not training its police force fast enough to take over security responsibilities as a U.N. peacekeeping mission in the West Africa country draws down, a U.N. official warned Tuesday.

Karin Landgren, the U.N. special representative for Liberia, praised the country for celebrating 10 years of peace on August 18, the anniversary of the end of a 14-year civil war. But she said the weakness of Liberia's security forces raises concerns about the country's ability to maintain stability on its own.

"The country should be proud of its significant achievements," Landgren said. "And yet it remains fragile, with a sense of unified nationhood still a work in progress, and small-scale outbreaks of violence still routine."

Landgren says only 99 officers graduated in the last year from the Police Academy, even though it was expanded to train 600 a year. The graduation of another 148 recruits has been delayed since May due to budget constraints.

The Security Council decided last year to cut the 8,500-member U.N. peacekeeping force in Liberia by more than half by 2015. The mission was established in 2003 when 15,000 troops were sent to help Liberia recover from the civil war.

Landgren said the U.N. no longer has a fixed military presence in four of Liberia's counties, although it has formed police units to back up the Liberian National Police.

"The Liberian security forces have not been able to scale up their presence and operational effectiveness to assume the increased security responsibilities," Landgren said.

In an address to the Security Council, Liberian Defense Minister Brownie J. Samukai acknowledged that "personnel and logistics constraints remain huge challenges" for the national police. He said "acute financial shortfalls linked to unmet revenue projections" have hampered police training.

He said the government remains committed to the transition plan and has allocated $10 million in its 2013-2014 budget for the security and justice sectors.

But Landgren said the budget "reduces allocations for the police significantly from last year."

She said a high-level retreat will be held next week, co-sponsored by the Liberian government, the United Nations and Sweden to discuss a "more focused, prioritized approach" to building up Liberia's security institutions.