The European Union's counterterrorism chief says the 28-nation bloc has been unable to stem the outflow of European recruits to radical Islamic groups in Syria and Iraq.

Gilles de Kerchove told a European Parliament committee on Monday the number of Europeans joining the Islamic State group and similar extremist organizations has "stabilized" in some EU countries, like Belgium and Britain.

But he said jihadi departures continue unabated from other EU member states, including France and Germany.

More than 4,000 Western Europeans have already gone to fight in the Middle East.

In February, the EU heads of state and government made shutting off the flow of additional jihadi recruits from Europe a priority. Asked to assess progress, De Kerchove said "we have not been able to stem the flow yet."