In the travel warning, posted on the State Department's website, the department recommended all but essential travel be avoided to the province of South Kivu and the Ituri region in the province of Orientale.
"With ongoing instability and violence in North and South Kivu, northeastern Orientale, and northern and central Katanga province, the department's ability to provide consular services to U.S. citizens in these regions of the DRC is extremely limited," the warning said.
Armed groups, bandits and elements of the Congolese military are security concerns in the eastern part of the African country. the warning said.
The armed groups "are known to pillage, steal vehicles, kidnap, rape, kill, and carry out military or paramilitary operations in which civilians are indiscriminately targeted," the State Department said.
"Travelers are frequently detained and questioned by poorly disciplined security forces at numerous official and unofficial roadblocks and border crossings throughout the country," the warning said. "Requests for bribes in such instances are extremely common, and security forces have occasionally injured or killed people who refused to pay."
The State Department warned of poor roads, high crime, lack of transportation options and inadequate healthcare delivery systems in the DRC.