The United States, Japan, Australia, Britain and New Zealand on Friday launched a new initiative to step up engagement with Pacific island countries, as China seeks to boost economic and defense cooperation with them.

Under a mechanism named "Partners in the Blue Pacific," the five countries said they will pursue "more effective and efficient" ways to deal with challenges such as "growing pressure on the rules-based free and open international order."

"As our countries — Australia, Japan, New Zealand, the United Kingdom, and the United States — continue to support prosperity, resilience, and security in the Pacific, we too must harness our collective strength through closer cooperation," they said in a statement.