The U.S. authorized the first evacuations of Americans out of Japan and warned U.S. citizens to defer all non-essential travel to any part of the country as unpredictable weather and wind conditions risked spreading radioactive contamination.

Issei Kato / Reuters

A passenger waits for an international flight at Narita international airport, east of Tokyo on March 17.

The decision to begin evacuations mirrors moves by countries such as Australia and Germany, who also advised their citizens to consider leaving Tokyo and other earthquake-affected areas. Tokyo, which is about 170 miles from the stricken nuclear complex, has reported slightly elevated radiation levels, though Japanese officials have said the increase was too small to threaten the 39 million people in and around the capital.

Issei Kato / Reuters

French citizens queue to check-in to a special charter flight to Paris, at Narita airport, east of Tokyo on March 17. The French government said on Wednesday that Japan was losing control of the situation at the Fukushima nuclear power plant and urged its nationals in Tokyo to leave the country or head to southern Japan.

"Based on scientific evidence there is absolutely no reason to leave Tokyo," Noriyuki Shikata, Japan's deputy Cabinet secretary for public relations, told NBC News on Thursday.

ChinaFotoPress via Getty Images

Chinese nationals arrive at Zhoushuizi International Airport in Dalian, Liaoning Province, China on March 16 after being evacuated from Japan. Thousands of Chinese nationals are being evacuated from earthquake-hit areas of Japan.

Read the full story and see more images in our slideshow.