A group of 70 Americans, including noted filmmaker Oliver Stone, on Tuesday criticized U.S. Ambassador Caroline Kennedy for her backing of a contentious U.S.-Japan plan to relocate a Marine Corps base within Okinawa.

The U.S. Marine Corps Air Station Futenma "must be closed, but moving it to Henoko isn't the solution," the group said in a statement referring to the bilaterally agreed but locally opposed relocation site, adding, "It merely shifts the problem to a less conspicuous location."

Kennedy told the Japan National Press Club in Tokyo last week that the plan to move the main function of the Futenma airfield from a densely populated urban area in Ginowan to a new facility in the Henoko coastal area of Nago, both in Okinawa, is "the best of any other plans that were considered."

Her statement is "a threat, an insult and a challenge for the vast majority of Okinawans who are vehemently opposed to the (relocation) plan," the group said.

The group urged Kennedy to reread a speech her father, John F. Kennedy, delivered in 1963 at American University in which he rejected a "Pax Americana enforced on the world by American weapons of war."

The 70 signers of the latest statement include scholars, peace advocates, journalists and a former senator.

Okinawa Gov. Takeshi Onaga, elected to oppose the plan to relocate the Futenma base within his prefecture, has lately been involved in a court battle with the government over his attempts to block the ongoing preparatory work to construct a replacement airfield in the sea.

The Japanese and U.S. governments agreed to the relocation plan as a way to reduce the burden on Okinawa, which already hosts the bulk of U.S. military facilities in Japan, while maintaining a security deterrence in the region.