The United States on Wednesday circulated a draft UN Security Council resolution proposing an arms embargo and targeted sanctions against South Sudan if President Salva Kiir refuses to sign a peace accord ending the country's civil war.
The draft resolution would kick in only if Kiir continues to delay signing the peace accord past the September 1 deadline to do so, according to a US official.
The Security Council is expected to vote on the resolution by that deadline.
"The idea is to shape behaviour ... in the next 15 days," the official told reporters Wednesday.
"There is one choice left to make, and that is the choice for peace."
The resolution would include an arms embargo against the world's youngest nation as well as targeted travel bans and asset freezes.
US Ambassador to the UN Susan Rice threatened to pursue sanctions on Tuesday after Kiir refused to sign a power-sharing deal intended to bring an end to a two-year civil war between his government and rebels that has killed tens of thousands of people.
Rebel leader Riek Machar signed the deal Monday, but Kiir only initialled part of it before saying he would finish signing it later.
Earlier Wednesday, the US State Department said Secretary of State John Kerry had spoken with Kiir, who assured him he intended to sign the deal.