United Nations - Liberia is assuming responsibility for its security for the first time since civil war ended in the West African country 13 years ago, a move welcomed by UN Secretary-General Ban Ki-moon.
A UN peacekeeping force transferred responsibilities on Thursday, and President Ellen Johnson Sirleaf will mark the handover on Friday.
A reduced UN force of about 1 200 troops will remain in a supporting role.
Ban paid tribute to Liberia's determination "to work towards lasting peace," his spokesman said.
The peacekeeping force was deployed in 2003 to help stabilise Liberia after a four-year civil war. That conflict and a previous civil war are said to have killed more than 250 000.
During the Ebola virus outbreak in 2014, Liberia's UN ambassador called a strong international presence in the country "a critical stabilising factor."
