BRATISLAVA (Reuters) - Hungary, Poland, the Czech Republic and Slovakia are ready to veto any Brexit deal that would limit their citizens’ rights to work in Britain, Slovak Prime Minister Robert Fico said on Saturday.

Slovakia's Prime Minister Robert Fico arrives for the European Union summit- the first one since Britain voted to quit- in Bratislava, Slovakia, September 16, 2016. REUTERS/Leonhard Foeger

EU leaders met in Slovakia’s capital Bratislava on Friday at their first summit for decades without Britain after a shock British vote in June to leave the bloc, a subject which Fico said had only been touched on at the meeting.

They are still trying to find common ground on the best way to cope with a higher number of migrants and how to shake off the lingering effects of years of economic crisis.

Fico said in an interview the EU had also shifted from a debate over mandatory quotas to a new principle of “flexible solidarity” over the migrant crisis.

The Visegrad group (V4) of Central European countries have together opposed EU efforts to introduce mandatory quotas for migrants and now, Fico said, also have a common interest in protecting citizens’ rights to work in Britain.

“V4 countries will be uncompromising. Unless we feel a guarantee that these people (living and working in Britain) are equal, we will veto any agreement between the EU and Britain,” he said. “I think Britain knows this is an issue for us where there’s no room for compromise.”

EU officials on Friday also underlined that there could be no granting Britain access to the EU’s single market unless London accepts the freedom of movement of workers that lies at the heart of European Union accords.

Fico reiterated that he was opposed to any “cherry-picking” in negotiations, saying EU freedoms must remain.

Britain has said it would not initiate the formal proceedings this year but it could do so next year, starting a two-year countdown to its exit.

The Brexit vote has triggered what European Commission President Jean-Claude Juncker has described as an “existential crisis” for the EU and Friday’s informal meeting of the bloc’s 27 members was meant to display unity but instead showed divisions remain over migrant policy.

The EU’s eastern members have been at odds with older members, mainly Germany, over taking in a share of more than one million migrants who last year fled war and poverty in Middle Eastern and African countries to come to Europe.

On Friday, Hungary criticized Germany for refusing to agree to a ceiling on the number of migrants entering Europe, saying it would continue to draw masses to Europe.

Fico said he wanted more steps on migration issues in the bloc’s new road map but that he was happy that border security was getting more attention and that a debate began on “flexible solidarity” allowing countries to offer what they can to tackle the migrant crisis.

“I could have banged on the table yesterday ... but that would get us nowhere. What the EU is about today, is lets talk about things that unite us. There is no time for things that divide us,” he said.

Slovakia has been one of the harshest critics of quotas and has sued the bloc over a plan agreed last year to re-distribute migrants, but was outvoted. Hungary has also taken legal action.

Fico said V4 would keep putting forward its common positions, which he said were sometimes more pragmatic given its history of transformation after the collapse of the Soviet bloc.

“But the V4 would never go against the EU. We will have our original positions, but we will not push it at the price of damaging the EU,” Fico said.