"The international order is supporting its agents and meddling in our internal affairs," the group said on Twitter.
"America the terrorist has added us to its terror list for repelling attacks by criminal bodies on our country," Agnad Masr – which means "soldiers of Egypt" in Arabic – asserted.
It added: "No America, you won't rule over us and you won't interfere on our soil. We are not an American state and we know where the true battle is and who we are fighting."
On Thursday, the U.S. State Department added Agnad Masr to its list of foreign "terrorist" groups.
Last month, the group claimed responsibility for a bombing that injured five policemen near southern Cairo's Helwan University.
An Egyptian court in May also designated Agnad Masr a "terrorist organization."