The US has imposed sweeping sanctions on former Democratic Republic of Congo President Joseph Kabila, accusing him of backing the M23 rebel group.

Washington alleges he provided financial support, encouraged defections from the Congolese army and even "sought to launch attacks" on the military from outside the country.

The 54-year-old ex-president, who led DR Congo for 18 years from 2001, has not responded to a BBC request for comment.

The US said these latest sanctions were part of a wider effort to support last year's peace deal between neighbours DR Congo and Rwanda that it brokered. Washington also says Rwanda supports the M23 and sanctioned some of its army's leading commanders in March.

Kigali denies backing the rebels, despite overwhelming evidence, and says its military presence in the region is a defensive measure against threats posed by armed groups in DR Congo to Rwanda's security.