Thousands of protesters are marching through Goma, the main city in eastern Democratic Republic of Congo, accusing Rwanda of backing local rebels.
Kinshasa has expelled the Rwandan ambassador, accusing Kigali of supporting the M23 rebels.
Rwanda denies this.Eastern DR Congo has seen a spike in hostilities this month as the M23 advance towards Goma.
The UN peacekeeping force has been put on high alert.A mostly Congolese Tutsi group, the M23 resumed fighting late last year after lying dormant for years.
It accuses Kinshasa of failing to honour an agreement to integrate its fighters into the army.Protesters march to the border of the Democratic Republic of Congo and Rwanda in Goma.