It's a World Heritage Site whose unique wildlife helped Charles Darwin to devise his theory of evolution.

Now the waters surrounding the Galapagos Islands, an archipelago some 900 kilometers (560 miles) off the Pacific coast of Ecuador, have become the latest point of friction between the world's two superpowers.

The appearance of hundreds of Chinese fishing vessels near the borders of the protected nature reserve prompted a rebuke from U.S. Secretary of State Michael Pompeo. China's government said it's being smeared by U.S. politicians trying to "sow discord".

The volcanic islands, which belong to Ecuador, are known for their abundance of indigenous species, including the huge Galapagos tortoise and the group of bird species known as Darwin's finches. The waters too are plentiful in marine life.