They should then plan for a complete withdrawal by 15 May.
The Zimbabwean Defence Minister, Stanislaus Mudenge, whose country backs the Congolese government, said the UN resolution was an important first step.
At the end of a three-day meeting on the DRC, the United Nations Security Council set a new timetable for the pull back of the different factions.
Efforts to end the two-and-a-half year conflict have come to a head recently following the death of former DR Congo President Laurent Kabila.
Agreement
In a resolution negotiated with all the parties, the council has demanded that the forces start an initial 15km (10 mile) pull-back by 15 March.
They should then plan for a complete withdrawal by 15 May.
"Of course it's only the beginning of a long journey, but it's a good beginning," said French Ambassador Jean-David Levitte.
The UN has plans to deploy 3,000 troops in DR Congo to monitor the withdrawals.
The Namibian President, Sam Nujoma, speaking after talks with President Joseph Kabila in Kinshasa, said: "We want to give the Congolese people the opportunity to free themselves and to commence the expected democratisation process so as to freely choose their leaders."
Pull back
There are about 50,000 foreign troops from African countries in DR Congo.
Rwanda and Uganda, which support the rebels, have already announced plans to pull back some of their troops.
Rwanda said it would unilaterally pull all its troops back 200km from current positions, starting at midnight on 28 February as a goodwill gesture which it hoped the Congolese Government would imitate.
Uganda said on Tuesday it would withdraw 1,000 of its forces from Congo.
Cautious optimism has grown since last month's assassination of Congo President Laurent Kabila.
But even if foreign forces do withdraw from the country, it will be an enormous task to fashion a functioning government with any real control of the Congo's vast territory.
Fighting over its rich natural resources has brought it to the brink of disintegration.