A late June agreement between Sudan and South Sudan to increase crude output from the south raised hopes of cooperation that could help the two struggling economies. But Juba is withholding crude that Khartoum expects to receive in August.

Contrary to promises made by the country’s energy ministry, South Sudan did not cease its crippling diversions of crude to Sudan in June, according to trading data seen by MEES.

Energy Minister Ezekiel Lol Gatkuoth said in late February that Juba...