U.S. Secretary of State Hillary Clinton is urging Rwanda and other regional states to cut off aid to a rebel group that has seized land in the eastern Democratic of Congo.

The top U.S. diplomat says the rebel group M23 is a serious threat to regional stability and security.

The group of army mutineers launched a violent rebellion in April and has since defeated the Congolese army in parts of the region.

The United Nations has accused the Rwandan government of actively supporting M23, which is made up of ethnic Tutsis. The Rwandan government has denied that charge.

During a news conference in Pretoria, South Africa on Tuesday, Clinton expressed support for talks on M23 taking place in Kampala, Uganda. The talks include high-level officials from Uganda, Rwanda and DRC.

“We urge all the states in the region including Rwanda to work together to cut off support for the rebels in the M23, to disarm them and to bring their leaders to justice,” she said.

Last month the United States cut some military aid to Rwanda because of concerns that Kigali was supporting M23.

The DRC has tried for years to subdue rebel groups in the mineral-rich eastern region.

Clinton expressed support for Congo's efforts and said the Kampala talks are “a good start.”

The U.S. diplomat was in South Africa as part of her 11-day tour of the continent.