President Donald Trump said nothing Monday in response to Russia's planned expulsion of hundreds of American diplomats, announced over the weekend by President Vladimir Putin.

"Right now we're reviewing our options, and when we have something to say on it we'll let you know," White House spokeswoman Sarah Huckabee Sanders said Monday after Trump's silence continued through several public appearances.

Asked when Trump would sign the bill passed last week by Congress, levying new sanctions on Russia, that precipitated the Kremlin's move, Sanders said that "we'll let you know when that's going to happen."

Whatever Trump decides to do in response, the fast-moving series of events appeared to leave the administration with no substantive Russia policy and without a clear idea of what direction to take.

It was left to Vice President Mike Pence, on a visit to NATO member Estonia, to note obliquely that "we hope for . . . better relations with Russia," but that "recent diplomatic action by Moscow will not deter" U.S. defense of its Baltic allies against Russian "aggression."

Putin said in a Moscow television interview late Sunday that he expected U.S.-Russia relations to worsen and that Russia may come up with other forms of sanctions retaliation.

Just as Trump did not mention Russia on Monday, Putin's spokesman indicated that Trump was irrelevant to the Kremlin's decision to retaliate before the new sanctions bill took effect. Passed with massive majorities in the House and Senate, "it will de facto become a law even if the U.S. president does not sign it," spokesman Dmitry Peskov told reporters in Moscow. "So there was no need to wait," he said. "Things are pretty obvious."

While Russia remained interested in improvements - promised by Trump during his campaign - relations for now were "far from this ideal," Peskov said.

Putin waited a half year to respond to a decision by President Barack Obama, in the waning days of his administration, to sanction Russia with diplomatic expulsions and property seizures in retaliation for cyber-intrusions in the U.S. electoral campaign. Trump has repeatedly expressed doubts about Moscow's culpability, and the Russians were clearly expecting a change in policy.

Russia had demanded the return of two diplomatic compounds in this country, labeled intelligence outposts by Obama, and applied for visas to send replacements for the 35 diplomats the previous administration kicked out.

But not only was no progress made on either issue, Trump's inability to stop the new sanctions legislation apparently led Putin to recalculate.

"The Russian government, I think, has largely written off Trump as a person who can deliver," said Andrew Weiss, vice president for studies at the Carnegie Endowment for International Peace and a Russia policy official during the Bill Clinton and George H.W. Bush administrations.

"But by the same token, they think there's no benefit in truly antagonizing him, and so they'll jolly him along for the indefinite future," Weiss said.

The chain of events began last summer, when U.S. intelligence told the Obama White House that Russia was behind email hacking and the spread of false news stories designed to promote chaos in the U.S. election and ultimately to benefit Trump. In late December, Obama expelled 35 Russian diplomats and the FBI took possession of Russian recreational compounds on Maryland's Eastern Shore and on New York's Long Island.

Surprisingly, Putin said he would not respond. Within weeks, the Justice Department became aware of conversations between Russia's Washington ambassador and top Trump aide Michael Flynn - soon to become Trump's first national security adviser - in which Flynn appeared to indicate that Trump's Russia policy would be more amenable to Moscow.

Over the ensuing months, as investigations into Russian electoral behavior and Trump's campaign expanded, U.S.-Russia relations had ups and downs. At the United Nations, Russia has stood fast against new sanctions on the Syrian government and North Korea, even as it negotiated a partial Syrian cease-fire with the United States.

In early July, Trump held his first face-to-face meeting with Putin, at the G-20 summit in Germany. The White House said Trump confronted the Russian leader over election meddling and that Putin had denied it. Putin said Trump accepted his denials. Both said they had agreed to move on to other subjects during their initial two-hour session.

In his readout of the meeting, Russian Foreign Minister Sergei Lavrov described it as "very specific," extending through North Korea, Syria, Ukraine and cybersecurity, and down into the weeds of Russia's long-standing demands that the United States release two long-jailed Russian nationals - arms dealer Viktor Bout and Konstantin Yaroshenko, a Russian pilot arrested in Liberia for arms smuggling and extradited to this country.

"We are continuing to work on this issue," Lavrov said. "We expect our American counterparts to make the right choice."

Nowhere has Russia been more adamant about the "right choice" than its demands that the United States return its Maryland and New York properties. Although the administration had indicated to Moscow that it was willing to do so, under certain circumstances, no deal was struck. Putin clearly grew tired of waiting.

"It's always been just a matter of time before the Russians decided to do something to punish the United States for the expulsions and the seizure," Weiss said. "The sanctions legislation is a complicating factor that basically precipitated" a new low in the relationship, he said, "but we've been marking time in many respects."

Unlike Obama, who ordered the expelled Russians to leave this country within 72 hours, the Kremlin said it would wait until Sept. 1 for 755 U.S. diplomatic employees to wind up their affairs, and that Washington could choose which ones would leave. Although there are more than 1,200 people working at the U.S. Embassy in Moscow and three consulates, only about 300 are believed to be Americans.

The Russian government also is seizing two U.S. diplomatic properties - a dacha, or country house, outside Moscow, and a warehouse.