AKIPRESS.COM - US President Barack Obama has signed a memorandum to expand a vast marine reserve in the Pacific Ocean.

The Pacific Remote Islands Marine National Monument will become the largest network of oceanic protected areas in the world.

The memorandum bans commercial fishing, deep-sea mining and other extraction of underwater resources in the area.

Environmental campaigners welcomed the move although some critics say President Obama could have done more.

"This really is a matter of stewardship. It's also a matter of generational responsibility," said US Secretary of State John Kerry.

"We have a responsibility to make sure... the future has the same ocean to serve it. Not to be abused, but to preserve and utilise."

The Pacific Remote Islands Area consists of seven scattered islands, atolls and reefs that lie between Hawaii and American Samoa.

The waters that surround these islands are home to corals, seabirds, sharks and vegetation not found anywhere else in the world, reports BBC.