Fast food giant McDonald's is to recall 12 million drinking glasses in the United States over fears that they could be toxic.

The 16 oz (454g) glasses were available in four designs promoting the launch of the new Shrek movie and could contain cadmium, according to US media reports.

The US Consumer Product Safety Commission warned consumers to stop using the glasses immediately because of fears that the metal could leach from the paint onto children's hands and be ingested if the child then put their hands in their mouth.

It has not been confirmed whether the glasses were available in Canada or other territories.

Cadmium is known to damage the liver, kidneys, lungs, nervous system and brain, although the warnings were related to long-term exposure.