BRDO PRI KRANJU, Slovenia, Jan 25, 2008 (AFP) - EU interior ministers gave a positive assessment Friday of security in Europe's expanded no borders zone, saying they had detected thousands of suspect migrants in less than a month.

'The system works,' said Slovenian Interior Minister Dragutin Mate before chairing a meeting of his European Union counterparts at Brdo Pri Kranju, central Slovenia.

'We stopped on our border more than 1,700 people' identified as potential suspects in the Schengen passport-free area's data base, 'and confiscated more than 140 cars stolen in the European Union,' he said.

Slovenia, which holds the EU's rotating presidency until June, was one of nine mainly ex-communist states to open their land a sea borders with the Schengen zone on December 21.

Controls at airports are set to be lifted on March 30, bringing the total number of countries in the zone to 24, including non-EU countries Iceland and Norway.

'We have got a huge number, I would say thousands and thousands of hits at crossings all across Europe,' said Justice Commissioner Franco Frattini, referring to matches between people and data on the Schengen computer system.

Some ministers noted a migration of people seeking asylum from the new states deeper into the EU, notably Chechens moving from Poland into Austria and Germany.

'We stopped many illegals in the border area,' said Interior Minister Guenther Platter, adding that 'Austria has reinforced controls.'

'We had a problem with Chechens who demanded asylum in Poland,' he said. 'The preparations are being made' to return them there.

Luxembourg Justice Minister Luc Frieden said: 'There was certainly a slight increase in the number of asylum seekers who were already in the European Union.'

'But there were no great movements of people which we could impute to the opening of the borders, which was a historic step,' he said.

Mate said it was too early to fully assess the impact the Schengen enlargement was having, and that his presidency would closely watch developments over the next six months to get a better picture.