An officer was killed and three others injured when gunmen opened fire on an army bus in Cairo, Aljazeera reported.
The Egyptian army said the Muslim Brotherhood was behind the attack, according to Reuters news agency on Thursday.
"Masked armed men belonging to the terrorist Brotherhood targeted a bus of the armed forces... which led to the martyrdom of the Warrant Officer Yusri Mahmoud Mohamed Hassan," the army spokesman said in a statement on Facebook.
Gunmen riding a motorcycle attacked the bus in the Amiriya neighbourhood of Cairo.
Egypt's state news agency and state television confirmed the death of one officer and the injury of three others.
Personnel from the security directorate deployed at the scene of the attack, under the command of General Mohamed Qasim, head of the investigations directorate for the capital, local media reported.
A security cordon was established in the area and traffic redirected while the investigation was under way.