The Donald Trump administration is calling on nations that import the bulk of oil from the Gulf to help protect freedom of navigation in the region after the United States blamed Iran for attacking shipping vessels.

The vice chairman of the Joint Chiefs of Staff, Gen. Paul Selva, said today that the Pentagon and State Department had approved plans to reach out to China, Japan, Singapore, South Korea, Indonesia and other oil importers about a possible response to defend tanker traffic. He did not offer any details about what those nations may be asked to do.

“This is a bigger problem than the free flow of oil,” Selva told a group of defense reporters. “It’s a country taking unilateral action. I think there is a military role in defending freedom of navigation. The question will be to what extent the international community will get behind that role.”

But the Pentagon’s planning appeared to be further scrambled today when President Trump announced that Shanahan’s presumptive nomination to be defense secretary would not be moving forward, following media reports of domestic violence allegations from a former marriage. Army Secretary Mark Esper, a former Raytheon lobbyist, will assume the role on an acting basis, Trump said.