The US State Department nominated experienced Africa hand Donald Booth as a special envoy to Sudan on Wednesday, hoping he can help craft a "peaceful political solution" between the military rulers and groups seeking civilian rule.

The nomination comes nine days after government troops and paramilitaries cracked down on protesters outside army headquarters in Khartoum, killing more than 110 and wounding hundreds over several days.

Booth, 65, knows the country well, having served as the Obama administration's special envoy to Sudan and South Sudan over 2013-2017.

State Department spokesperson Morgan Ortagus said Booth is already at work, traveling with Assistant Secretary of State for African Affairs Tibor Nagy to Sudan "to engage with the parties."