Sofia (AFP) - Eastern European countries opposing new refugee quotas should show more solidarity with the European Union, Bulgarian Prime Minister Boyko Borisov said Thursday, adding that Sofia would accept its share of people fleeing war and persecution to Europe.

In an interview with AFP, the conservative Bulgarian premier said that poorer EU countries that depend on aid from Brussels should return the favour by helping to ease the migrant burden on western European countries.

"When taxpayers (in richer European countries) give money for European solidarity, we are happy. When, however, they have a problem -- because the migrant flow is mainly headed there -- then, in my view, we also have to show solidarity and mutual aid," Borisov said.

The migrant crisis has sparked a rift between some western European countries, who back an EU quota system to share asylum-seekers among member states, and several central and eastern European countries like Hungary, Poland and Slovakia who reject the mechanism.

Bulgaria stood apart from the group of ex-communist countries this week in confirming that it would accept its quota of 1,200 refugees.

So far, however, only two Iraqi refugees have agreed to be relocated to Bulgaria from other EU countries, one of whom has already slipped out of the country.

"The migrants do not want to stay in Bulgaria. They want Sweden, Luxembourg, Switzerland. Do we need to build a prison to keep them here by force?" Borisov added.

The prime minister, a former bodyguard, expressed scepticism about a proposed EU "solidarity contribution", or fine, of 250,000 euro ($290,000) per refugee that member states decline to take in.

"It is high time that European Union members find mechanisms that work in practice instead of just condemning each other with statements along the lines of 'whoever does not accept relocation will be fined'," the sharp-tongued Borisov said.

- Too proud to plead -

Bulgaria had been bracing for an influx of migrants across its borders with Greece and Turkey after the western Balkans route was sealed off earlier this year.

But so far, Borisov said, there had not been any increased pressure along the 259-kilometre (160-mile) border with Turkey or the 493-kilometre frontier with Schengen member Greece, to the south.

The Balkan country has put up a three-metre-high fence along 95 kilometres of its porous border with Turkey. The fence will eventually stretch to 132.5 kilometres. Around 2,000 border police, gendarmes and soldiers have been deployed to patrol the rest of the border.

"Bulgaria has taken tough measures to guarantee the security not only of its people but of the European Union," Borisov said.

Taking aim at Greece, he said his cabinet had received migration aid of "a mere 6 million euros from the European Union compared to 700 million euros for our neighbours Greece".

"Bulgaria has proved that it is was doing much better in safeguarding the Schengen area than the Schengen member states themselves".

Bulgaria and its northern neighbour Romania, who joined the EU in 2007, had been refused entry into the passport-free Schengen zone following objections from a number of EU members led by the Netherlands.

"It was insulting," Borisov said, adding that Sofia had no intention of asking for a re-think on the matter.

"We are a proud nation and to plead with a country to see the obvious just won't happen," he said.