BRUSSELS, March 23 (Xinhua) -- European Union (EU) leaders said here Friday they regretted the decision by the United States to impose import tariffs on steel and aluminium, adding these measures could not be justified on the grounds of national security.

The spring European Council, held on Thursday and Friday, focused on economic affairs, in particular on trade, where EU leaders noted that shipments of steel and aluminium from the bloc had been temporarily exempted from tariffs, and called for that exemption to be made permanent.

The EU leaders supported the steps taken by the European Commission to respond to the U.S. measures as appropriate and in a proportionate manner.

They also reaffirmed the EU's commitment to an open and rules-based multilateral trading system with the World Trade Organization (WTO) at its core.