Plans for rebels in the Democratic Republic of Congo to withdraw from the eastern city of Goma have been hampered by a dispute over supplies.
The M23 rebels had said they would move to a position 20 kilometers outside the strategic provincial capital by the end of the day Friday, while leaving about 100 soldiers at the airport.
As the withdrawal showed signs of getting under way, a dispute erupted between the rebels and United Nations peacekeepers over abandoned army supplies that the insurgents wanted to take with them.
The rebels accused peacekeepers of blocking their withdrawal. The peacekeepers said they cannot allow the rebels to take army supplies, which include ammunition.
In another development Friday, the U.N. Security Council imposed sanctions against two M23 rebel leaders. The council issued a global travel ban and assets freeze against Baudoin Ngaruye and Innocent Kaina, both senior rebel leaders. It already has ordered similar sanctions against M23's top military leader, Sultani Makenga.
Meanwhile, Britain has suspended $30 million in aid to Rwanda, following accusations that country's government is supporting M23.
The British Department for International Development said Friday it was acting on "credible and compelling reports of Rwandan involvement with M23."
There was no immediate reaction from Rwanda, which has denied supporting the group.
M23 rebels have begun leaving other areas of the eastern DRC, including the nearby town of Sake.
The rebel group had seized control of Goma last week after fighting with the Congolese army and U.N. peacekeepers. M23 was supposed to leave the city under a regionally-brokered deal.
Some 270 police officers who fled Goma when the rebels took over are waiting to re-enter the city.
M23 consists of former rebels who were integrated into the Congolese army, but deserted early this year complaining of discrimination and poor treatment.
The DRC government has tried for years with little success to pacify the east, where armed groups compete for control of the region's mineral wealth.