Britain will introduce sanctions soon against Rwanda over fighting in neighbouring Congo, a minister in the UK Foreign Office told Reuters on Monday.

Asked if Britain would impose sanctions on Rwanda, Ray Collins, who covers Africa policy as a junior minister in the foreign office, replied "Yes". Asked when, he said "Soon".

The "UK has made its position clear to Rwanda and will act soon," he added, speaking to Reuters on the sidelines of a U.N. Human Rights Council meeting in Geneva.

Rwanda is facing global pressure over allegations it supports the M23 group which, since January, has captured swathes of eastern Congo including the cities of Goma and Bukavu, and valuable mineral deposits.

Kigali denies backing the group but says its own troops are acting in self defence against hostile groups based in Congo.

On Thursday the U.S. Treasury imposed sanctions on James Kabarebe, a high profile ally of Rwandan President Paul Kagame, accused by Washington of serving as "a Rwandan government liaison" to M23. Rwanda said the sanctions were unjustified.