The UN Security Council has unanimously approved a resolution allowing European Union troops to use force in the Central African Republic and threatening sanctions against those blamed for the country's strife.
The EU has pledged 500 troops to help African and French forces already in the country trying to end clashes between rival Christian and Muslim militias.
The resolution allows the reinforcements to use "all necessary measures" to protect civilians in the country which has been in near anarchy since its president was overthrown by rebels 10 months ago.
Michel Djotodia, who replaced the ousted president, resigned this month along with his prime minister after failing to check the religious violence.
Following the resignation, Catherine Samba-Panza, the mayor of Bangui, the capital, was elected interim president of the Central African Republic, making her the first woman to hold the post.
The UN resolution allows for sanctions against the ringleaders of groups blamed for massacres and human rights abuses, but did not name initial targets for measures.
It also calls on the Central African Republic's interim government to speed up moves towards new elections.
A transitional accord between rival groups set a deadline of February next year for elections. The council said polls should be held in the second half of 2014 if possible.
Gerard Araud, France's UN ambassador, said the resolution was "a new stage" in efforts to help the Central African Republic out of the strife in which thousands are feared killed and more than 900,000 people have fled their homes.
"There is an incredible amount of resentment and hatred between the two communities," he said of the clashes between Muslim and Christian groups, but added that there are signs of improvement.
Separately, thousands of jubilant residents took to the streets of Bangui to celebrate on Tuesday after peacekeepers escorted dozens more rebels from military bases in the latest sign the fighters are losing their grip on the country.
Their departure from Camp Kasai comes a day after others left the hillside Camp de Roux in central Bangui for another base on the northern outskirts, witnesses said.
Other top brass from the Seleka movement were escorted by peacekeepers north of the capital on Sunday, and were believed to be heading towards neighbouring Chad.
"We are liberated! This is our New Year!" the crowds shouted as the rebels left under the protection of French and African regional forces.