(CNN) -- A week before South Sudan is expected to split from Sudan and declare its independence, the United States sent a special envoy to the region in an effort to foster a smooth transition between the two countries.
Princeton Lyman, the Obama administration's special envoy for Sudan, departed Washington Saturday, according to a written statement from the U.S. Department of State.
He was en route to Addis Ababa, Ethiopia, and is expected to join former South African President Thabo Mbeki in support of ongoing talks between officials in Khartoum, Sudan and Juba -- a fast-growing city soon to become South Sudan's new capital.
The two men are expected to lend support to a peace agreement that ended Sudan's second civil war, and help moderate potential conflicts over resource sharing, disputed border areas and citizenship matters, the statement said.
But the visit also comes on the heels of controversy.
The 2005 Comprehensive Peace Agreement afforded Abyei, a sparsely populated region that straddles Sudan's north-south border, with special status that required militaries to remain outside the area until inhabitants voted on its destiny.
But in May, troops from Sudan took control of Abyei in retaliation for what they claim was an attack by Southern Sudanese forces on a U.N. convoy carrying Sudanese troops.
The takeover was followed by violence, looting and the displacement of tens of thousands of people, later prompting representatives of both sides to sign an agreement calling for the immediate withdrawal of Sudanese troops from the disputed Abyei region.
The agreement, signed in Addis Ababa, also called for the deployment of a brigade of Ethiopian troops to serve as peacekeepers.
Lyman is expected to travel to Khartoum for meetings with senior Sudanese officials, the statement said, and then to Juba to attend South Sudan's independence ceremony on July 9.
His trip also follows a controversial four-day visit to China by Sudanese President Omar al-Bashir, who is wanted by the International Criminal Court for alleged atrocities committed during the civil war in Sudan.
China, however, did not see the ICC's indictment as a reason to block al-Bashir's visit.
"China is not a party to the Rome Convention, is not a member of the ICC and is not legally bound to implement the ICC's decision," said Liu Guijin, China's special envoy to Africa.
Sudan is China's third-largest trading partner in Africa, while China is Sudan's largest trading partner.
Experts estimate that more than 60% of Sudanese oil output is purchased by China and accounts for more than 6% of Chinese imported oil.
But analysts say the July 9 split will afford South Sudan with more than two-thirds of the country's oil-producing regions.
"The north, Bashir's regime, is going to suffer much less oil revenue," said Stephanie Kleine-Ahlbrandt, China and North East Asia Project Director of the International Crisis Group.
For al-Bashir, that could spell a budget crisis, spiraling inflation and further political instability.
Human rights groups like Amnesty International have criticized China for inviting al-Bashir to visit, saying that China will become "a safe haven for an alleged perpetrator of genocide."
Al-Bashir has denied allegations of atrocities.