By Lesley Wroughton
WASHINGTON (Reuters) - The Trump administration on Wednesday imposed sanctions against two senior South Sudanese officials and the country's former army chief in a warning to the government of President Salva Kiir over increasing attacks on civilians and aid workers in the country's four-year civil war.
The U.S. Treasury Department, in a statement on its website, said it had blacklisted Malek Reuben Riak Rengu, deputy chief of defence for logistics in South Sudan's army; Paul Malong, former army chief sacked by Kiir in May and put under house arrest; and Minister of Information Michael Makuei Lueth for their roles in destabilising South Sudan.
The measures freeze any assets in the United States or tied to the U.S. financial system belonging to the three men.
The crackdown comes days after Trump's new aid administrator, Mark Green, visited South Sudan to deliver a blunt message to Kiir that Washington was reviewing its policy toward his government.
The meeting signalled that the Trump administration was reconsidering its backing for Kiir, who came to power with the support of Washington when oil-rich South Sudan won independence from neighbouring Sudan in 2011 following decades of conflict.
But the world's youngest country dissolved into civil war in 2013 after Kiir, an ethnic Dinka, fired his deputy Riek Machar, a Nuer.
Nearly one-third of the country's population - or four million people - have fled their homes, creating the continent's largest refugee crisis since the 1994 Rwandan genocide.
In its statement, the Treasury said Malek Reuben played a central role in weapons procurement during the first few years of the conflict and helped plan an offensive in Unity State in April 2015 which targeted civilians and led to "numerous rights abuses."
It also accused him of issuing military contracts at inflated prices "in order to receive extensive kickbacks." In 2015, it was suspected Malek Reuben was fabricating procurement contracts for food for government troops, the Treasury added.
The U.S. Treasury blacklisted All Energy Investments, A+ Engineering, Electronics & Media Printing, and Mak International Services which it said was owned or controlled by Malek Reuben.
Malong was sacked by Kiir in May as army chief and put under house arrest in the capital Juba, the country's defence minister told Reuters last week.
But the U.S. Treasury said he was being designated for his involvement in obstructing peace talks as well as international peacekeeping, diplomatic and humanitarian missions in South Sudan.
The Treasury statement said Malong was reportedly responsible for attempted efforts to kill Machar in 2016 and "did not discourage" the killing of civilians in operations around the town of Wau last year.
It said Malong was found with "currency worth millions of U.S. dollars in his possession" belonging to the military's treasury as he tried to flee Juba in early May.
The U.S. Treasury accused Makuei of attacks against the United Nations mission in South Sudan, as well as obstruction of peacekeeping and humanitarian missions in the country.
(Reporting by Lesley Wroughton in Washington; Additional reporting by Maggie Fick in Nairobi; Editing by Tim Ahmann and James Dalgleish)