“We are all aware of the intensification of discussions in Europe on the subject of strengthening the defence component of the EU,” he told a telephone briefing with journalists.
“There are various transformations that we are observing in the most careful way.”
Elsewhere, the European Commission also proposed making Moldova an EU membership candidate.
The Commission concluded that Moldova, which shares a long border with Ukraine, has reached a solid basis to further alignment with EU rules and regulations, the EU’s executive said in a statement.
The EU’s last major enlargement was in 2004 when eight formerly communist eastern countries - including the Baltic States, Poland and Slovenia - joined. Romania and Bulgaria followed in 2007.