The US sanctions a Rwanda official and a rebel spokesperson over violence in Congo

The United States on Thursday sanctioned a Rwandan government minister for his alleged role in the conflict in neighbouring Congo, where Rwanda-backed rebels are battling the Congolese army and have captured two key cities.

Along with the Rwandan minister for regional integration, James Kabarebe, the U.S. sanctioned Lawrence Kanyuka Kingston, a spokesperson for the M23 rebels. Two companies linked to Kanyuka and registered in Britain and France were also sanctioned.

The M23 rebels are the most prominent of more than 100 armed groups that have been vying for control of eastern Congo’s trillions of dollars in mineral wealth.

The rebels' unprecedented expansion followed years of fighting. The M23 group took control in a lightning three-week offensive, first seizing eastern Congo’s main city, Goma, and then the second-largest city, Bukavu, on Sunday.

The U.S urged “the leaders of Rwanda to end their support for M23” and withdraw all Rwandan troops from Congo. U.N. experts say there are about 4,000 troops from Rwanda in Congo.

The U.S. State Department spokesperson Tammy Bruce said in a statement that the U.S. also calls on Congo and Rwanda's governments “to hold accountable those responsible for human rights violations and abuses.”

The U.S. announcement said Kabarebe, the Rwandan minister who is also a retired military officer, has been liaising with the M23 rebels and handling the revenue and export of minerals that the Rwanda-backed rebels have procured in eastern Congo.

“Today’s action underscores our intent to hold accountable key officials and leaders like Kabarebe and Kanyuka,” said Bradley T. Smith, an acting undersecretary of the Treasury.

Rwanda's foreign ministry called the sanctions “unjustified and unfounded."

“Punitive measures, including sanctions, make no contribution toward long-term security, peace and stability for all the countries of the Great Lakes region,” said the ministry.

Since the start of the M23 rebels’ offensive on Goma on Jan. 26, more than 700 people have been killed and nearly 3,000 have been wounded in the city and its vicinity, officials say.