U.S. officials on Monday affirmed that “now is the time to leave” for Americans currently in Ukraine, as fears about a possible Russian invasion into the country spiked on Monday.

The State Department’s spokesperson said he did not have a count of how many Americans remained in the country, since many don’t register when traveling there, but the department had already directed U.S. embassy staff and their families to leave Kyiv.

“We are conveying very clearly now that now is the time to leave,” said White House press secretary Jen Psaki. “There's commercial airlines, you can depart over land. There's obviously the embassy there to provide assistance.”

“But there is not an intention or a plan for any military evacuation,” Psaki added, noting there would not be a massive effort like the one in Afghanistan in late August that aimed to evacuate U.S. citizens, residents and allies.

State Department spokesperson Ned Price could not say on Monday how many Americans were left in Ukraine, since people are not required to register and deregister when traveling to and from the country.

“We just don't have an accurate tally at the moment,” Price said. “We have encouraged them to fill out a form that will help us acquire greater granularity on the size of the private American citizen community.”

The department also changed its travel advisory on Sunday to be stronger than the previous warning against traveling to Ukraine because of COVID-19 as well as the tensions over Russia.

“Do not travel to Ukraine due to the increased threats of Russian military action and COVID-19. Exercise increased caution in Ukraine due to crime and civil unrest. Some areas have increased risk,” the department advised.

The State Department on Sunday also ordered the families of all American personnel at the U.S. Embassy in Ukraine to leave the country amid heightened fears of a Russian invasion.

Officials told the dependents of staffers at the U.S. Embassy in Kyiv that they must leave the country. It also said that non-essential embassy staff could leave Ukraine at government expense.

State Department officials stressed the Kyiv embassy will remain open and that the announcement does not constitute an evacuation. The move had been under consideration for some time and does not reflect an easing of U.S. support for Ukraine, the officials said.

Ukraine’s Foreign Ministry spokesman, Oleg Nikolenko, said the U.S. decision was “a premature step” and a sign of “excessive caution.” He said Russia is sowing panic among Ukrainians and foreigners in order to destabilize Ukraine.

Asked about the similarities to the U.S. exit from Afghanistan, the State Department spokesperson on Monday said the two situations were “not analogous” and reiterated there would not be a U.S. government-led evacuation of Americans from the country.

“Given the large-scale military buildup, we've also been clear that we won't be in a position to evacuate U.S. citizens — private U.S. citizens — in such a contingency,” Price said. “The embassy is there to assist American citizens in this. We have the ability to provide, for example, repatriation loans for any Americans who seek to avail themselves of those commercial options to return to the United States.”

The Associated Press contributed to this report.