Diplomats say that Russia and Angola have opposed moves at the UN Security Council to impose sanctions on a South Sudan general and a rebel commander accused of stoking conflict.

The US had proposed a travel ban and asset freeze on army Chief Paul Malong and rebel General Johnson Olony for his alleged role in fuelling conflict.

The Russian ambassador to the UN said sanctions might aggravate the situation, AP news agency reports.

Fighting has continued in South Sudan despite last month's peace deal.

Both sides signed the agreement to end the 20 months of conflict under intense regional and international pressure.

The fighting between forces loyal to President Salva Kiir and his former deputy Riek Machar has forced more than 2.2 million people from their homes in the world's youngest state, which broke away from Sudan in 2011.