Did the United States' internment involve Japanese foreign nationals?

Question

The mayor of Roanoke, Virginia, David Bowers, wrote in a statement

President Franklin D. Roosevelt felt compelled to sequester Japanese foreign nationals after the bombing of Pearl Harbor, and it appears that the threat of harm to America from Isis [sic] now is just as real and serious as that from our enemies then

He has since apologised for offending people, but hasn't said that he got the facts wrong.

Did the United States only, or predominantly, involve Japanese foreign nationals in its internment program in WWII?

I know it's not 100% correct because Italians and Germans were also interned, but I want to know if the statement is even vaguely close to the truth. The Washington Post article mentions

It was not just Japanese foreign nationals but Japanese-American citizens who were put in camps during World War II. In 1988, the U.S. government officially apologized for the policy and paid $20,000 to each survivor of what was deemed the result of “race prejudice, war hysteria and a failure of political leadership.” In the end more than $1.6 billion was distributed in reparations.

but doesn't indicate what proportion weren't "Japanese foreign nationals", or define what "Japanese-American" means (someone with Japanese ethnicity, or Japanese nationality?).

Answer 1

From National archives:

Roosevelt's order affected 117,000 people of Japanese descent, two-thirds of whom were native-born citizens of the United States. The Issei were the first generation of Japanese in this country; the Nisei were the second generation, numbering 70,000 American citizens at the time of internment. Within weeks, all persons of Japanese ancestry--whether citizens or enemy aliens, young or old, rich or poor--were ordered to assembly centers near their homes. Soon they were sent to permanent relocation centers outside the restricted military zones.

More information on Japanese immigrants citizenship in this article: Who are the Issei, Nisei, Kibei, and Sansei?

Answer 2

I want to give an alternative answer from a local (Virginia) point of view.

Close to Roanoke, Virginia (where Bowers is mayor) are the luxury resorts Homestead and Greenbrier.

Immediately after the bombing of Pearl Harbor, Japanese, Germans, Italians, Hungarians, Bulgarians, and Romanians were held at these luxury hotels. These were foreign nationals (diplomats and their families).

The University of Virginia law library makes many primary references concerning this internment of Japanese foreign nationals available in the collection:

Greenbrieir Hotel Mission

As a summary see Diplomats, Disputes & Deceit World War II's First Exchange of Enemy Diplomats :

Ten days later on December 17, an executive at the Greenbrier Hotel, deep in the Appalachian Mountains, at White Sulphur Springs, ... Just after lunch the manager received a telephone call from a representative of the Chesapeake and Ohio Railroad (C&O), the owner of the hotel, who inquired if the Greenbrier would be interested in housing the Axis diplomats, their families and the nationals of various enemy countries. Later that evening a second call was taken by the hotel management from the State Department informing staff of an order issued by President Roosevelt that the foreign diplomats of the warring nations were to be removed from the nation's capitol within 48 hours and taken to the Greenbrier. The staff was then advised of the imminent arrival of the uninvited guests and were reminded they were "avowed agents of a hostile governments and to be aware some were undoubtedly the directing heads of fifth column activities in the United States."

The Protocol Division of the State Department advised the hotel when such officials are caught in a country during war, the diplomats are entitled to living conditions according to their customary living standards which, in the United States, would be maintained as far as possible while awaiting their return to their homeland.

The United States Government official in charge of overseeing the detention of the internees at the Greenbrier Hotel and Virginia's Homestead Hotel, the locations for the internment, was Roy L. Morgan, special agent for the FBI. He was to monitor the activities of 1,200 European and Japanese diplomats confined to the two hotels from December 1941 until June 1942, while waiting repatriation to their home countries. During this period Agent Morgan filed many confidential memoranda to J. Edgar Hoover concerning the activities of the detainees. The reports to Hoover contained a wealth of information regarding the Japanese diplomatic mentality and efforts of espionage in the United States.

The mayor's statement "President Franklin D. Roosevelt felt compelled to sequester Japanese foreign nationals after the bombing of Pearl Harbor" is clearly true.

It is also true that Roosevelt later issued executive order 9066

...I hereby authorize and direct the Secretary of War, and the Military Commanders whom he may from time to time designate, whenever he or any designated Commander deems such action necessary or desirable, to prescribe military areas in such places and of such extent as he or the appropriate Military Commander may determine, from which any or all persons may be excluded, and with respect to which, the right of any person to enter, remain in, or leave shall be subject to whatever restrictions the Secretary of War or the appropriate Military Commander may impose in his discretion.

This order was used by General DeWitt to establish a specific west coast zone thousands of miles away from Virginia from which Japanese (including Korean and Taiwanese) ethnicity persons were excluded. This eventually led to internment of both Japanese foreign nationals and US citizens who remained in the military exclusion zone as well addressed by the other answer.