"President Barack Obama on Thursday will designate the largest marine sanctuary in the world in an area of the Pacific Ocean that will be off-limits to commercial fishing and deep-sea mining, the White House said on Wednesday.

Obama will sign a proclamation that increases the size of the Pacific Remote Islands Marine National Monument by six-fold to 490,000 square miles (1.27 million sq km/370,000 sq nautical miles).

The White House said in a statement the area is "of particular interest because science has shown that large marine protected areas can help rebuild biodiversity, support fish populations, and improve overall ecosystem resilience."

Eric Beech reports for Reuters September 25, 2014. [2]