The US Embassy in Cairo condemned on Friday with the "strongest terms" the attack on Egypt's deputy prosecutor-general Zakaria Abd El-Aziz Azmy in New Cairo Thursday, an embassy statement read.
A car bomb detonated as Azmy was heading in his convoy in the First Settlement area of New Cairo to his office.
The prosecutor and his guards escaped unscathed but a passerby was injured.
The US embassy, in the statement published on Facebook, described the attempted assasination on Azmy as "an attack against one of the most important institutions in Egyptian society," adding that perpetrators must be brought to justice.
A little-known Egyptian militant group, named Hasm, claimed responsibility for the attack, threatening further attacks against what it described as "the oppressive judiciary," AFP reported.
In June 2015, Egypt's late top prosecutor Hisham Barakat was assassinated in a similar bomb attack by militants near his home in Cairo.