Yokota Air Base is home to U.S. Forces Japan in western Tokyo.

YOKOTA AIR BASE, Japan — The U.S. military has ordered extra scrutiny for South Koreans who want to visit friends or attend events on American bases in Japan.

U.S. Forces Japan recently added the longtime American ally to a list of nations whose citizens must undergo additional screening before they can be escorted onto installations.

A copy of the list posted near the entrance to the home of USFJ in western Tokyo now features South Korea alongside about 50 other nations, including North Korea, China, Russia, Iran and Afghanistan.

“No personnel will escort a designated third country national onto Yokota Air Base,” says a sign posted next to the list, which also includes France. “It is the responsibility of the escort sponsor to verify the individual is not from one of the … designated countries.”

USFJ did not provide a reason for the new checks on South Koreans.

People from designated third countries aren’t authorized to enter U.S. bases in Japan without prior coordination of supporting agencies and approval by the installation commander, said Air Force Maj. Genieve White, a USFJ spokeswoman.

Each request is looked at on a case-by-case basis and requires written and detailed information of potential guests to adequately coordinate the request, she said, referring to a past Air Force instruction.

“We are not banning anyone,” White added. “This instruction does not apply to immediate family members of a sponsor or a sponsor’s spouse that are citizens of a designated third country.”

Screening requirements vary depending on the individual and the purpose of their visit, White said. She recommended that sponsors contact security forces 30 days ahead of a planned visit by someone from one of the designated countries.

Japanese citizens carrying a passport can be escorted onto U.S. bases in South Korea without additional checks, according to officials at Osan Air Base, home of the 51st Fighter Wing south of Seoul.

It had been common for South Koreans in Japan to visit friends and relatives married to U.S. servicemembers who live in on-base housing.

Sunha Park, a South Korean housewife living near Yokota, said she was turned away after trying to visit friends at the base last week.

“I was so surprised,” she said. “A month ago, I could be on base right after just taking a photo.”

Park said she and her friends have been regular guests in American homes and at Yokota’s chapel.

“I don’t feel good,” she said of the change. “It seems that we’re treated like criminals. Such an action makes me think ‘Have I done something wrong? Has our country’s people done something wrong?’”

Stars and Stripes correspondent Yoo Kyong Chang contributed to this report from Seoul.

robson.seth@stripes.com

Twitter: @SethRobson1