A McDonald's outlet in Mexico was shut down after a customer reported finding a rat's head inside a burger, reported the media on Tuesday.

However, the fast food chain denied the allegations claiming it was an extortion bid by the customer, reported EFE news.

The outlet in Tlalnepantla de Baz city was shut after the customer published photos of the burger containing a rat's head on social networking sites, which were then published by the Mexican press.

McDonald's spokesperson Felix Ramirez told "El Universal" newspaper that the incident would be investigated, but did not rule out the possibility of an extortion attempt by the consumer.

"We are trying to find out what happened; it is something that was planted; it is impossible that something like that could be served at one of our restaurants," he said.