A top U.S. official has warned both Kenya and Uganda against allowing corrupt South Sudanese investors into their countries, VOA Swahili reported on Wednesday.

Sigal Mandelker, the U.S. Undersecretary for Terrorism and Financial Intelligence, said Ugandan and Kenyan leaders must stop allowing South Sudanese officials to buy up property with corrupt proceeds.

Mandelker, who is touring Africa this week, told reporters at the American Embassy in Kampala that the U.S. government has made it clear to Ugandan and Kenyan lawmakers and bankers it is their responsibility to stop corrupt South Sudanese officials from taking illicit funds derived from the four-and-a-half-year conflict and investing it in Ugandan and Kenyan property.

“This trip really provides us with the opportunity not only to speak to our government counterparts but also financial institutions, NGOs about how human rights abusers and others are using the regional and international financial systems to hide illicit money.

“One of my top priorities as a senior administration official is holding accountable those who abuse human rights, perpetrate corruption and undermine democratic ideals of justice,” Mandelker said.

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The warning to Kenya and Uganda comes at a time the two nations seems to be on a cold diplomatic spat after the Ugandan forces arrested several Kenyan - including three police officers - and fishermen at the Hama Islands, leading to the a further arrest of '53 Illegal Ugandan immigrants' by Kenyan authorities on Tuesday. The 53 were travelling from Uganda to Kenya via road.