FILE PHOTO: Democratic Republic of the Congo's President Joseph Kabila is pictured inside his office at the Palais de la Nation building in Gombe municipality in the capital Kinshasa, Democratic Republic of the Congo April 3, 2017. REUTERS/Kenny Katombe/File Photo

KINSHASA (Reuters) - Congolese President Joseph Kabila has replaced the national police chief of police and the police commander in the capital Kinshasa, as security concerns rise following his refusal to step down when his mandate expired.

Mass prison breaks, kidnappings, rising militia violence and surging lawlessness since Kabila failed to step down in December have raised fears Democratic Republic of Congo could slip back into the chaos and conflict of the turn of the century that killed millions.

About 4,000 inmates escaped from Kinshasa’s main prison in May and unidentified assailants killed at least two people and wounded six police officers in an attack last Friday on the city’s largest market, leading some Kabila allies to call for a state of emergency.

In an decree read late Monday evening on national television, Kabila named Dieudonne Amuli Bahigwa to replace Charles Bisengimana as chief of the national police.

Amuli is a veteran army general who led military operations in eastern Congo in 2009 against the Democratic Forces for the Liberation of Rwanda (FDLR), one of the largest and most dangerous armed groups operating in the region.

Sylvano Kasongo Kitenge was named to replace Celestin Kanyama as head of police in Kinshasa. Kanyama came under U.S. and EU sanctions last year for alleged human rights violations by the police in suppressing anti-Kabila protests.

A presidential election to replace Kabila, in power since 2001, was scheduled for last November but was postponed due to delays registering voters.

Congo’s election commission head said this month it would probably not be possible to hold the vote this year, leading Kabila’s opponents to threaten further street demonstrations.

(This story corrects to make clear Kanyama came under EU and U.S., not UN, sanctions, in paragraph 6.)