Washington is mulling over the most effective way to pressure South Sudanese President Salva Kiir into peace and reconsidering the efficacy of withdrawing aid, Reuters reported Tuesday.

Withdrawing aid may not work, US Envoy to the United Nations Nikki Haley said ahead of a visit to South Sudanese refugees in Gambella in western Ethiopia the same day.

Approximately 350 000 refugees have fled across the border into Gambella after South Sudan descended into civil war and chaos in 2013 – barely two years after gaining independence from Sudan.

“You have to really think hard before you pull US aid because President Kiir doesn’t care,” Haley said. “He doesn’t care if his people suffer and that’s the concern we have as we don’t know that will make a difference.

“That’s a conversation we will have and we will try and see exactly what will move President Kiir so that he does start to really look at creating a safe position for his people,” she told reporters in Addis Ababa late on Monday.

The American diplomat will also meet with Kiir when she visits South Sudan this week as part of her six-day trip to the region where she is holding consultations with African Union (AU), UN and government officials.

But before she meets with Kiir, Haley wants to see the reality on the ground vis a vis the South Sudan conflict spilling over into deadly cross-border raids into Gambella by gunmen from South Sudan.

Mark Green, President Donald Trump’s new administrator, visited South Sudan last month and warned Kiir that Washington was reviewing its policy towards his government before calling on the president to stop the violence by implementing a real ceasefire.