Police in the Belgian capital Brussels have used water cannon and tear gas on protesters hurling bottles and stones ahead of an EU summit.
Scuffles began when a small group of protesters moved into the Rue de la Loi, a street close to the summit venue in the city's European quarter.
The group reportedly grew in size as the confrontation increased.
Thousands of other demonstrators have been protesting peacefully in the city against EU austerity cuts.
Trade unions called on them to challenge moves to commit governments to a new "Euro Pact" that seeks to moderate wages in a bid to make Europe's economy more competitive against global rivals.
The two-day summit of the EU's 27 heads of state and government is due to start at 1600 GMT.
"The European Commission's annual examination of growth as well as the competitiveness pact launched by German Chancellor Angela Merkel and French President Nicolas Sarkozy will drag wages and social rights down to dangerous levels," Belgium's CES union said in a statement.