Two children were killed when a tree limb fell on their tent at Yosemite national park in California, the US national park service says, The Guardian reported.
The limb fell from an oak tree at Upper Pines campground in the Yosemite Valley at approximately 5am on Friday. Park rangers responded but found both children dead.
The names and ages of the children were not released, and the incident is being investigated, the park service said in a statement.
"Our thoughts are with the families as they grieve this tragedy," said park superintendent Don Neubacher.
The Upper Pines campground is a popular area of the park about 200 miles due west of San Francisco.