Dozens of mpox patients being treated in hospital isolation units in Goma have fled for their lives as violence engulfs the eastern Democratic Republic of Congo, the WHO said Friday.

Meanwhile the UN refugee agency warned that hundreds of thousands of civilians were fleeing to areas beyond the reach of humanitarian aid, after shelters for displaced people were destroyed.

The M23 armed group, supported by Rwandan forces, has made advances in the province of South Kivu since Wednesday, after a few days of respite following a rapid offensive that saw its fighters claim the city of Goma in North Kivu province at the end of January.

The World Health Organization said there had been 1,348 laboratory-confirmed mpox cases in DRC this year until February 2, with no deaths. "DRC in general is the worst-affected country for mpox," spokesman Christian Lindmeier told reporters.