SANTO DOMINGO -- More than 4,950 UN peacekeepers have left Haiti since 2011, as part of a withdrawal plan announced by UN Secretary-General Ban Ki-moon, the world body's peacekeeping force in the country said Thursday.

Nigel Fisher, head of the UN Stabilization Mission in Haiti (Minustah), said in an open letter posted on the UN website that in keeping with the scaleback, the peacekeeping forces' budget has also been reduced by 30 percent.

The Haitian government and Minustah have been holding talks to consolidate the UN troop withdrawal plan since last February, based on the progress made on key goals such as beefing up Haiti's national police, he said.

"We are in the process of improving the plan to ensure it is feasible and contains clear indicators for the strengthening of national institutions and the reduction of Minustah's presence," Fisher said.

Last year, the UN Security Council said the number of Minustah troops should be based on the security situation in Haiti and the country's increasing capacity.

Fisher said a joint working group is supervising the plan's execution, adding that economic resources that become available due to the plan will be transferred to UN peacekeeping missions in other countries.

"I am sure both the Haitian and international actors agree that the gradual and orderly withdrawal of Minustah from Haiti is desirable and necessary," he said. "They also agree that the withdrawal is tied to the progressive strengthening of Haitian institutions that are key for security, the elections and the rule of law."

Minustah was established in 2004 to replace the multinational forces authorized by the United Nations following then Haitian president Jean Bertrand Aristide's exile and an ensuing instability in the country.

In October 2011, Ban informed Haitian President Michel Martelly of his goal to begin a gradual withdrawal of the mission.