(Reuters) – The U.S. Embassy to Ukraine urged Americans living in Ukraine to leave immediately, stating that security in Ukraine was unpredictable due to Russian military actions.

According to the Embassy, “the security situation can deteriorate quickly”, it stated on its website https:// Wednesday.

The United States warned its citizens to avoid traveling to Ukraine earlier this week.

U.S. President Joe Biden indicated Tuesday that, while it is a very rare action, personal sanctions on Russian President Vladimir Putin can be taken as part Washington’s effort to persuade Moscow that any further aggression against Ukraine will have rapid and huge costs.

Russia said Wednesday that while sanctions against Putin will not directly harm him, they would have a “politically damaging” effect.

Russia is assembling tens to thousands of troops close to its border with Ukraine, but denies that it intends on invading.

American diplomats have spent many weeks trying to reach an agreement with European partners about a robust sanctions package in case Russia attacked.