Witnesses say clashes have broken out for a second consecutive day in Central African Republic's capital in the worst violence the city has seen since a United Nations force took over peacekeeping last month.

Pieterjan Wouda of Doctors Without Borders said heavy weapons could be heard Thursday morning. He said staff with the humanitarian organization would stay home because of the dangers.

The violence began Tuesday when a former fighter with a mostly Muslim rebel coalition that toppled the president last year was killed, prompting reprisal attacks.

At least 5,000 people have died over nine months of sectarian violence in the country, which is currently led by a transitional president.