The impending US military action against Syria, which indicates that the superpower might continue its entanglements in the Middle East, has raised questions about the US' pivot to Asia strategy.

The White House said on Tuesday that President Barack Obama called Japanese Prime Minister Shinzo Abe on Monday evening to discuss their grave concerns about the use of chemical weapons in Syria on Aug 21.

"They pledged to continue to consult closely on possible responses by the international community," the White House statement said.

In the phone call, the two leaders also reaffirmed the critical role of the US-Japan alliance for the peace and stability of the Asia-Pacific.

"They stressed their shared commitment to taking steps to further enhance security cooperation on regional and global challenges, and to continue implementing our shared plan for US force posture realignment in Japan," the statement said.

Michael Auslin, a resident scholar and director of Japan studies at the American Enterprise Institute, a conservative think tank in Washington, believes the crisis in Syria shows that the Asia pivot is rhetorical.

"While the administration was claiming a new era in US foreign policy, the ghosts of crises past continue to disturb Mr Obama's dreams," Auslin wrote in the Wall Street Journal on Monday. "Renewed violence in Iraq and the complexities of not losing all gains in Afghanistan after the withdrawal of US troops in 2014 were perhaps highest on the list of unfinished business. Yet more concerning were the brewing crises: Iran's continued pursuit of nuclear weapons and the bloody Syrian civil war."

Auslin described the real world intrusions of failing US diplomacy as spelling trouble for Obama's pivot. "It is entirely likely that long-term deployment of Pacific-based units to the Middle East could be needed to ensure that Syria's war does not spill over," he said.

Auslin believes that the Syrian issue will further fuel China's distrust of the US' strategic intentions.

He said Syria shows that Obama is stretched in keeping both promises and commitments around the world. "Far from making Asia more stable, the pivot may well wind up alienating both friends and competitors alike," he said.

Bonnie Glaser, senior advisor for Asia at the Center for Strategic and International Studies, disagreed that the Syria crisis will distract the US from its Asia pivot strategy.