GENEVA (Reuters) - The United States lodged an appeal on Friday to challenge a World Trade Organization ruling it said had failed to bring its meat labelling laws into line with global trade rules.

Canada and Mexico won a WTO ruling three years ago that said the U.S. rules illegally discriminated against imported meat.

The United States lost a subsequent appeal and was told to bring its laws into line, but in October this year the WTO said it had not done so, paving the way for Canada and Mexico to demand the right to impose trade sanctions.

Canadian Agriculture Minister Gerry Ritz said Ottawa was deeply disappointed by the appeal and called on the United States to drop its "blatantly protectionist" labelling rules.

"We will take whatever steps may be necessary including retaliation to achieve a fair resolution," he said in a statement.