Two ready meal ranges sold by Aldi have been found to contain up to 100% horsemeat, it has been confirmed.
As supermarkets and suppliers prepare to meet to discuss the food labelling scandal, the company said it felt "angry and let down" by its French supplier Comigel, which also produced the contaminated Findus beef lasagnes.
Tests on Today's Special frozen beef lasagne and Today's Special frozen spaghetti bolognese found they contained between 30% and 100% horse meat, Aldi said.
The meals were withdrawn earlier this week as a precautionary measure and the firm has urged consumers to return the products.
An Aldi spokesman said: "Tests have been completed that show horse meat in the withdrawn products. In samples selected at random, tests demonstrated that the withdrawn products contained between 30% and 100% horse meat.
"This is completely unacceptable and like other affected companies, we feel angry and let down by our supplier.
"If the label says beef, our customers expect it to be beef. Suppliers are absolutely clear that they are required to meet our stringent specifications and that we do not tolerate any failure to do so.
"We have acted quickly to withdraw the affected products from sale, conduct additional testing and review the performance of our suppliers. The products from Comigel will not be sold in our stores again and we will no longer take any product from Comigel."
Anyone who has bought the affected products can receive a full refund, Aldi said.
The company added that it would test the meals for the veterinary drug phenylbutazone, often referred to as "bute", but said it was "confident" the meals were safe.
"We are determined to learn from this and avoid any repeat", the spokesman added.
"We already have rigorous testing systems in place, but clearly we need to do more to ensure that our suppliers are complying with our high standards.
"Aldi will not tolerate any supplier who fails to comply with our requirements and we will support any appropriate legal action taken against any supplier that knowingly does wrong."
Environment secretary Owen Paterson will hold an emergency meeting on Satruday with the Food Standards Agency (FSA) and retailers, as ministers warn of a "criminal conspiracy" at the heart of the horse meat scandal.
Frozen food company Findus UK has reiterated its apology after tests found up to 100% horse meat in some of its beef lasagnes, while claims emerged that the meals may have been contaminated since August.
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