A Sudanese woman carries a baby at the Zam Zam camp for internally displaced people in Darfur in April 2015. (ASHRAF SHAZLY/AFP/Getty Images)

As Mark Green, the head of U.S. humanitarian aid, visits hard-hit areas of Sudan to assess whether help is getting to millions of civilians uprooted by war, he frequently dangles a carrot — lifting sanctions and a trade embargo.

His first overseas trip since becoming administrator of the U.S. Agency for International Development (USAID) coincides with a sanctions review by the Trump administration that could undo measures imposed two decades ago. The White House has set an Oct. 12 deadline for a decision on whether to end sanctions against Sudan put in place initially over its support for international terrorism and then for the violence it used suppressing rebel groups in the five states that make up the Darfur region.

“The timing of my visit shows the importance the U.S. attaches to our relationship with Sudan during this very important sanctions review period,” Green said pointedly Monday as he met with Abdul Wahid Yousif, the governor of North Darfur state. The Sudanese official is credited with restoring the rule of law in a region where villages were destroyed when rebel groups battled government troops and pro-government militias in a brutal conflict that started in 2003.

“We will be closely watching for sustained progress,” Green added, citing five conditions Washington has laid down for sanctions relief, “especially humanitarian access.”

U.S. officials and many aid groups say the Sudanese government has made notable progress over the past year reining in lawlessness and allowing aid workers into conflict zones they had been blocked from reaching.

There also have been advances in counterterrorism cooperation. Sudan, where Osama bin Laden lived from 1992 to 1996, is one of three countries the United States labels a state sponsor of terrorism.

Sudan wants sanctions lifted so it can buy spare parts for its planes, trains and canal locks, which are crumbling. Its college graduates are fleeing the country for lack of opportunities. Inflation is running at around 34 percent annually. Khartoum hopes easing U.S. sanctions will open the door for foreign investment in energy, agriculture and precious metals.

But the decision is complicated by the fact that the president, Omar Hassan al-Bashir, is wanted by the International Criminal Court on charges of genocide related to the conflict in Darfur, in which an estimated 300,000 people have died.

Many say constructive engagement would encourage changes for the better and lead to a greater influx of development aid.

“What we want to ensure is, while we are trying to get the regime to change its ways, that the people of Sudan are not suffering because of that,” said Steven Koutsis, the charge d’affaires at the U.S. Embassy in Khartoum. The United States has not had an ambassador in Sudan since 1997.

President Barack Obama announced before leaving office in January that the U.S. government would ease some financial sanctions against Sudan but that the measures would not fully take effect for months, allowing the Trump administration to continue or reverse the policy.

Many aid workers favor eased sanctions. Marta Ruedas, the U.N. humanitarian coordinator in Sudan, said Sunday that aid workers have been admitted to areas long denied them. She credited the change of policy to negotiations between Khartoum and Washington over sanctions relief.

But a White House decision to lift sanctions is unlikely to have an immediate effect on Zam Zam camp, where 230,000 people are sheltered, less than 10 miles outside of El Fasher, the capital of Darfur. Many residents have lived there for over a decade.

Green, who became head of USAID three weeks ago, toured the camp Monday, listening as residents peppered him with questions.

About a dozen women learning how to grow crops, a project of Relief International, shook their heads vehemently when asked if they ever leave camp to collect firewood.

“It’s not safe,” said Hawa Abdallah Mohammad, 33, who has given birth to five of her seven children in Zam Zam camp and has lived there for 13 years.

Aid workers say violence remains a problem in some areas of Darfur, primarily because of local disputes.

The government is trying to increase safety through a disarmament campaign. Billboards show semiautomatic rifles, rocket-propelled grenades and masked gunmen all with a big red X through them, part of an effort to encourage people to turn in weapons voluntarily. In some areas of Darfur, the United Nations is holding workshops to try to discourage land-use conflicts between farmers and nomadic herders.

The government and aid agencies are hopeful that at least some residents at camps such as Zam Zam can start returning home soon. But some may never go back.

Haroom Nimr, 52, said that he fled his village in 2004, leaving behind a house where he raised sheep and land where he grew millet. Someone else is working the land now, he has heard. He does not want to risk confrontation and said he will not even try returning until he is assured the squatters have been evicted.

“I won’t go back,” he said as he and a group of men gathered under a tree to discuss what they had heard from Green. “I will probably sit here for the rest of my life.”