Chief Cabinet Secretary Hirokazu Matsuno holds a press conference at the prime minister's office in Tokyo on Jan. 24, 2022. (Kyodo)

Japan is considering evacuating its nationals in Ukraine amid fears of an imminent Russian invasion, Japanese government sources said Monday, following such an order by the United States to family members of its embassy staff.

The Foreign Ministry warned against traveling to Ukraine for any purpose. Its second-highest Level 3 advisory, which previously covered parts of the Eastern European country, now applies to the whole of the nation.

About 250 Japanese citizens including family of embassy staff live in Ukraine, according to the ministry.

Japan is also "moving in that direction," a senior ministry official said in reference to the U.S. order issued Sunday, while underscoring that "the situation is changing rapidly" in the Eastern European country.

Chief Cabinet Secretary Hirokazu Matsuno said the government has reminded Japanese residents in Ukraine to prepare for unforeseen circumstances.

"We will continue to closely monitor the changes in the situation and take necessary measures promptly while working closely with the United States and other related countries," the top government spokesman said at a press conference.

Tensions have been rising over a military buildup by Russia with estimated 100,000 soldiers along its border with Ukraine, with no progress seen in talks between Western nations and Moscow on European security issues.

Ukrainian servicemen are seen outside of Svitlodarsk, Ukraine on Jan. 23, 2022. (Anadolu Agency/Getty/Kyodo)