Firefighters protect giant sequoias as Yosemite blaze spreads

The cause of the Washburn fire was under investigation. It had grown to nearly 2.5 square miles (6.7 square kilometres) by Sunday morning

A firefighter protects a sequoia tree as a blaze burns in Mariposa Grove in Yosemite National Park (Noah Berger/AP)

A wildfire threatening the largest grove of giant sequoias in Yosemite National Park more than doubled in size in a day, with firefighters working to protect the iconic trees.

More than 500 mature sequoias were threatened in the Mariposa Grove in the sprawling park in California but there were no reports of severe damage to any named trees, including the 3,000-year-old Grizzly Giant.