South Sudan's president has promised to sign a peace deal he had earlier snubbed, the US State Department says.
Salva Kiir told US Secretary of State John Kerry he had decided to sign after "a couple more days of consultation", a State Department spokesman said.
His refusal on Monday to sign the deal to end an 18-month civil war was described as "mind-boggling" by the chief mediator.
The US said the latest developments were "encouraging".
But it has submitted draft proposals for a UN arms embargo on South Sudan.
The UN Security Council blacklisted six generals - three from each side - in July, but member states were at the time unwilling to impose further sanctions.
Fighting between government and rebel forces resumed following Mr Kiir's failure to endorse the deal on Monday.
Nearly two million people have been left homeless since conflict broke out in the world's newest state in 2013.
Fighting erupted in that year after Mr Kiir accused rebel leader Riek Machar, his former deputy, of plotting a coup.
Mr Machar signed the accord in Ethiopia's capital, Addis Ababa, on Monday - the deadline set by mediators.