Ministers would review progress in May and then it would be up to EU leaders meeting in June, or later in the year, to take "bold decisions if we want to deliver on defence and security," she said.
This could include efforts to relaunch a so-called rapid response force, which was approved as a rotating battle group led by member states a decade ago but never deployed, Mogherini told reporters.
"Now with crises all around, we hear from our partners, starting from the UN that a rapid reaction force from the EU would be needed to be deployed in some crisis areas," she said.
Mogherini has spearheaded efforts to give the EU the "hard power" to match its "soft power" influence. Britain, nuclear armed and with a permanent veto at the United Nations, long opposed such efforts, fearing the creation of a "European army" commanded from Brussels.