British Prime Minister David Cameron says criticism by an "unelected" Brussels official of his plans for tougher curbs on migrants is "totally inappropriate".
The prime minister said he had collared European Commission president Jose Manuel Barroso at a summit in Lithuania to complain about the intervention by EU employment commissioner Laszlo Andor.
Andor had criticised the government's benefit crackdown, warning Britain would be seen as "nasty" if it pushed ahead with the measures which he called "an unfortunate over-reaction".
Five weeks before Romanian and Bulgarian citizens get new rights to live and work in the UK, Cameron has set out radical plans to overhaul welfare rules, including stopping new arrivals from the EU receiving out-of-work benefits for their first three months in the country.
He says he wants to send a clear signal to would-be migrants that Britain is not a "soft touch".
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
But he is also pushing for wider EU reforms such as limiting the free movement of workers - seen as a fundamental principle of the EU - from new member states until they hit a certain level of GDP per head.
Over dinner in Vilnius he told EU and east European leaders it was impossible to press ahead with welcoming new countries to the Union "without addressing abuse of free movement and how it works in future", the UK government said.
Germany and France are among other key EU member states taking action on the benefits issue.
Cameron wrote on Twitter that he had raised Commissioner Andor's comments with Barroso and told him it was "totally inappropriate for unelected officials to complain about legitimate concerns".
A Number 10 spokesman said the prime minister made clear that such "behaviour is inappropriate for an official paid for by British and other European taxpayers.
"When elected European leaders are raising real and substantive concerns about an issue affecting people it is not for officials to dismiss those without any discussion," he said.
Under the new measures, citizens of EU countries will only be able to claim out-of-work benefits for a maximum of six months unless they can prove they have a genuine prospect of employment.
New migrants will not be able to claim housing benefits immediately.
Those found begging or sleeping rough could be deported and barred from re-entry for 12 months unless they can show they have a proper reason to be in the UK, such as a job.
