US President Barack Obama announced Thursday that two Russian compounds in Maryland and New York, used by Russian personnel for intelligence-related activities, will be closed. Access to the compounds will be denied to all Russian diplomats as of noon on Friday, "The New York Times" reported.

The State Department also declared 35 Russian intelligence operatives "persona non grata," meaning they must leave the country within 72 hours.

Washington has accused the Russian military's Main Intelligence Directorate (GRU) of hacking information with the intent to interfere with the US election - along with help from the Federal Security Service (FSB).

As part of the move, the US released a detailed analysis, conducted by the Department of Homeland Security and FBI, attributing the malicious cyber attacks to Russia. 

The FSB will face sanctions, along with four individual GRU officers, including agency chief Igor Valentinovich Korobov and three other entities.

Moscow has rejected the accusations of hacking and cyber-interference, calling them "unfounded," and warned it would consider retaliatory measures.

Late Thursday, a Kremlin spokesperson said the US sanctions "will destroy diplomatic relations with Russia."

Dmitry Peskov, the spokesman for Russian President Vladimir Putin, signaled that Moscow was now considering retaliatory measures against the US.

He told reporters that the sanctions characterized Obama's "unpredictable" and "aggressive foreign policy."

"Such steps of the US administration that has three weeks left to work are aimed at two things: to further harm Russian-American ties, which are at a low point as it is, as well as, obviously, deal a blow on the foreign policy plans of the incoming administration of the president-elect" Peskov said.

Leading Republicans welcome Obama's decision

With Donald Trump due to take office on January 20, Obama's move puts the president-elect in the position of having to decide whether to retract the measures once sworn in as president.

Trump has repeatedly signaled that he intends to take a softer stance toward Moscow.

Responding to news of the sanctions, Trump said it was "time for our country to move on to bigger and better things." However, he has pledged to meet with intelligence leaders next week to be "updated on the facts of this situation."

Despite Trump's stance, other leading Republicans appeared to welcome Obama's decision to impose sanctions, creating a potential wall of opposition should the incoming president seek to overturn his predecessor's measures. House of Representatives Speaker Paul Ryan, the top Republican in Congress, accused Russia of consistently seeking to undermine the US and said the sanctions were overdue.

Republican Senators John McCain and Lindsey Graham indicated they would head efforts to "impose stronger sanctions on Russia."

Earlier, Obama said he implemented the sanctions in response to the Russian government's "aggressive harassment of US officials and cyber operations" aimed at last month's US election.

"All Americans should be alarmed by Russia's actions," Obama said in a statement.

The president added, however, that the actions were "not the sum total of our response to Russia's aggressive activities."

"We will continue to take a variety of actions at a time and place of our choosing, some of which will not be publicized," he said.

In the coming days, Obama's outgoing administration is expected to provide a report to Congress regarding "Russia's efforts to interfere" in last month's vote, as well as other "malicious cyber activity" related to previous elections.

Russian reaction

In an interview with the RIA news agency, Konstantin Kosachev, a spokesman for the Russian parliament's upper chamber, described the measures as "the death throes of political corpses."

Kosachev told the Interfax news agency that Russia would wait to see how Trump responds to the sanctions before outlining any retaliatory steps. 

Russia's embassy in London, meanwhile, decried the Obama administration's actions as "lame," saying it harked back to Cold War relations. In a tweet, the embassy said it "will be glad to see the last of this hapless [administration]. Accompanying the tweet was a picture of a duck with the caption "lame" - a reference to the phrase "lame duck" used to describe outgoing governments.

Trump, Putin deny Russian motive for hacks

Three US intelligence agencies concluded earlier this month that Russia was behind hacks into the US Democratic Party and leaked documents ahead of the presidential election on November 8.

The agencies also agreed that Russia sought to intervene to help Trump and other Republican candidates into office. Both Russia and Trump have denied and dismissed the findings, with Trump accusing the Democrats of trying to delegitimize his election.

Trump has repeatedly praised the Russian president; on Saturday, Trump tweeted he agreed with Putin's assertion that Democratic presidential nominee Hillary Clinton did not display any "dignity" in her election defeat. 

Trump has also appointed people seen as friendly towards Moscow to senior positions in his administration, most notably his pick for secretary of state, former ExxonMobil CEO Rex Tillerson.

ksb, dm/cmk (Reuters, AFP, AP, dpa)