Authorities in Seoul have ordered Mars and Nestle to pull three products after melamine, which is usually used for making plastics, was detected in snacks made in China by the multinationals.
The industrial chemical had been found in M&M's milk chocolate snack and Snickers peanut Fun Size, both produced by Mars, and Kit Kat chocolate bars imported from Nestle Tianjin in China, Korea Food and Drug Administration said.
Melamine has been blamed for making thousands of infants ill and killing four in mainland China after it tainted baby milk powder in one of the country's worst ever product safety scandals.
• The European Union recently banned all imports on Chinese milk-related products for children such as biscuits and chocolate on top of a long-standing embargo on Chinese dairy products like milk and yoghurt.
• A fourth Chinese milk product has been withdrawn from sale in Australia after tests revealed it was tainted with melamine, Food Standards Australia New Zealand said in a statement.