JUBA, South Sudan (AP) — South Sudan opposition leader Riek Machar has returned to the country to meet with President Salva Kiir less than a month before their deadline to form a unity government after a five-year civil war.

Machar last met face-to-face with Kiir in September, when they discussed outstanding issues in a fragile peace deal. His two-day visit includes a meeting with the U.S. ambassador to the United Nations, who arrives Sunday with a U.N. Security Council delegation.

The delegation is expected to encourage progress in the peace deal signed a year ago.

The opposition has said Machar won't return to form the government by the Nov. 12 deadline unless security arrangements are in place.

The U.S. has said it will reevaluate its relationship with South Sudan if that deadline is missed.