The U.S. Embassy in Egypt urged its citizens to be cautious on Thursday following a bomb attack targeting the country's interior minister.
The Nasr City attack left at least 19 people injured, including a child and a British woman, but the minister himself was unharmed, the state news agency reported.
"This incident serves as an indicator of the tension and volatility that continues to exist throughout the country," a statement on the official website of the U.S. mission in Egypt said.
The embassy urged U.S. citizens to avoid large gathering and demonstrations, even if "intended to be peaceful", for confrontations may occur and escalate into violence.
It also urged citizens to avoid police stations and other places where security forces are present, pointing to the recurring attacks on security personnel since the ouster of Islamist President Mohamed Mursi.
"U.S. citizens in Egypt are urged to monitor local news reports and to plan their activities accordingly."