The United States has invited the leaders of China and Japan for prestigious state visits, President Barack Obama's top security adviser said Friday, signaling a deepening of his "pivot to Asia."

"In furtherance of our relationships throughout this vital region, I'm pleased to announce today that we have invited Prime Minister (Shinzo) Abe of Japan and President Xi Jinping of China for state visits," said National Security Adviser Susan Rice.

Rice also said that President Joko Widodo of Indonesia and President Park Chung-hee of South Korea would visit the United States this year as well.

Early in his presidency, Obama put forward plans to withdraw US military, economic and human resources from Middle East wars, deploying them to emerging Asia instead.

But he has sometimes struggled to keep the strategy on course given the Arab Spring, wars in Syria and Ukraine, and the economic crisis in Europe.

The visits -- which come on the back of a three-nation trip Obama made to Asia in November -- are designed to underscore that the strategy remains on track.

The announcement comes as the United States and Japan approach the final stage of talks on a vast trade agreement that would link a dozen countries on either side of the Pacific Ocean.

The timing of the state visits was not clear, but Abe's arrival is only expected after the conclusion of the trade deal, which still faces major hurdles.

President Obama has yet to ask Congress to give him authority to sign a deal, amid opposition from within his own Democratic party.

His negotiating partners want to see that authority in place before putting the final touches on an agreement, but issues like agriculture and auto tariffs are potential stumbling blocks.

Earlier on Friday, Obama's administration unveiled its National Security Strategy, which set out measures to "advance our rebalance to Asia and the Pacific."

"The United States has been and will remain a Pacific power. Over the next five years, nearly half of all growth outside the United States is expected to come from Asia," it added.

The document also welcomed the rise of a "stable, peaceful and prosperous China."

"While there will be competition, we reject the inevitability of confrontation. At the same time, we will manage competition from a position of strength while insisting that China uphold international rules and norms," the strategy document said.

Beijing has seen Obama's "pivot" to Asia as a possible attempt to contain China's meteoric rise, a claim Washington denies.

Xi's visit to the White House would be the first since becoming Chinese leader in 2013.