European farming ministers and the European commissioner for health were due to meet in Brussels Wednesday amid growing anger and recriminations over mislabelled meat products.
The EU meeting comes a day after British police searching for the source of horsemeat in kebabs and burgers raided two meat plants, the first such operation since the scandal spread across Europe.
The Brussels meeting takes place amid suspicions of links to organised crime and public fears over health, and a day after France became the second European country after Britain to confirm that frozen lasagne contained horse meat.
Supermarkets in Switzerland and the Netherlands pulled more ready-made meals from the shelves as a precaution.
Health and Consumer Affairs Commissioner Tonio Borg will host Wednesday's talks as anger grows over the EU's failure to act more quickly.
A spokesman for Borg said Tuesday it was too early to require labelling on meat used in processed foods but France's junior agriculture minister Guillaume Garot called for precise labelling on the origin of meat in ready-made dishes.
And Interbev, an association representing the French cattle and meat industry, denounced the EU's failure to act. Both consumers and professionals wanted swift action on better labelling, it argued in a statement.
In Britain, police and officials from the Food Standards Agency on Tuesday raided a slaughterhouse in northern England and a meat-producing factory in Wales. They shut both sites and seized all meat there.
The FSA said the Peter Boddy slaughterhouse in Todmorden, in the county of West Yorkshire, was believed to have supplied horse carcasses to Farmbox Meats in Aberystwyth, Wales.
"The agency and the police are looking into the circumstances through which meat products, purporting to be beef for kebabs and burgers, were sold when they were in fact horse," the agency said.
Andrew Rhodes, operations director of the FSA, said he had ordered an audit of abbatoirs that produce horsemeat in Britain when the scandal arose last month "and I was shocked to uncover what appears to be a blatant misleading of consumers."
British environment minister Owen Paterson said he expected the "full force of the law to be brought down on anyone involved in this kind of activity."
British supermarket Waitrose pulled frozen beef meatballs from its shelves after tests showed they may contain traces of pork, not listed as an ingredient.
The raids on the British meat premises opened a new front in the pan-European search for the source of the horsemeat: the allegations had so far focused on Romania.
In France, retailer Picard said tests had confirmed that horsemeat was present in two lots of frozen "beef" lasagne meals made by French firm Comigel.
Retailers in Britain, Sweden, France, Switzerland and the Netherlands have been removing Comigel products after the firm alerted Swedish frozen food giant Findus to the presence of horsemeat in its meals last week.
Swiss supermarket giant Coop told AFP Tuesday it had now withdrawn all frozen lasagnes produced by Comigel as a precaution.
Comigel denies any wrongdoing. It said it obtained its meat from another French firm, Spanghero, which said it was supplied from two abattoirs in Romania who allegedly passed off horsemeat as beef.
But Romanian Prime Minister Victor Ponta on Monday angrily denied his country was to blame and called on European Union officials to find out from where the fraud originated and identify the guilty parties.
Dutch supermarkets PLUS and Boni said Tuesday they had withdrawn Primafrost brand frozen lasagne as a precaution because it may contain horsemeat without being marked on the packaging.