In a sweeping response to election hacking and other meddlesome behavior, President Barack Obama on Thursday sanctioned Russian intelligence services and their top officials, kicked out 35 Russian officials and closed down two Russian-owned compounds in the U.S. It was the strongest action the Obama administration has taken to date to retaliate for a cyberattack.

"All Americans should be alarmed by Russia's actions," Obama said. He added: "Such activities have consequences."

In a bid to expose Moscow's cyber aggression, the U.S. also released a detailed report about Russia's hacking infrastructure that it said was designed to help computer specialists prevent more hacking. And Obama said more action was coming.

"These actions are not the sum total of our response to Russia's aggressive activities," Obama said in a statement released while he was vacationing in Hawaii. The U.S. has previously left open the possibility it could mount a retaliatory strike.

The spokesman for Russian President Vladimir Putin said the new sanctions were a sign of Obama's "unpredictable and, if I may say, aggressive foreign policy" and were aimed at undermining President-elect Donald Trump.

"We think that such steps by a U.S. 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, to deal a blow to the foreign policy plans of the incoming administration of the president-elect," Dmitry Peskov told reporters in Moscow.

Ahead of the announcement, Russia's foreign ministry had threatened to retaliate against American diplomats if the U.S. took action against Russian officials.

The White House has promised to release a report before Obama leaves office detailing Russia's cyber interference in U.S. elections, a move that could address Russia's complaints that the U.S. hasn't shown proof of its involvement. But the U.S. moved forward with the response Thursday even as the report has yet to be released.

Still, Obama administration officials said the list of entities Obama was sanctioning made clear who exactly the U.S. believes was behind hacking of Democratic groups and the theft of emails from Hillary Clinton's campaign chairman.

Obama ordered sanctions against two Russian intelligence services, the GRU and the FSB, plus companies which the U.S. says support the GRU. The cybersecurity firm hired by the Democratic National Committee to investigate theft of its emails determined earlier this year the hacking came from the Fancy Bear group, believed to be affiliated with the GRU.

The sanctions freeze any assets the entities or individuals have in the United States, and also block Americans from doing business with them. It wasn't immediately clear what impact they would have on the intelligence services' operations.

The FSB is Russia's main domestic and counter-terrorism intelligence agency. It was formed following the Soviet collapse when the KGB was split into the FSB and the foreign intelligence agency SVR. The GRU is the Russian military intelligence agency.

The president also sanctioned Lt. Gen. Korobov, the head of the GRU, and three of his deputies. Other individuals sanctioned include Alexei Belan and Yevgeny Bogachev, two Russian nationals who have been wanted by the FBI for cyber crimes for years.

Obama's move puts Trump in the position of having to decide whether to roll back the measures once in office, and U.S. officials acknowledged that Trump could use his executive authorities to do so.

U.S. allegations of hacking during the campaign have ignited a heated debate over Trump's approach to Russia and his refusal to accept the assessment of U.S. intelligence agencies that Russia's government was responsible and wanted to help him win. Though U.S. lawmakers have long called for Obama to be tougher on Russia, some Republicans have found that position less tenable now that Trump is floating the possibility of closer ties to Moscow.

"While today's action by the administration is overdue, it is an appropriate way to end eight years of failed policy with Russia," said House Speaker Paul Ryan, R-Wis.

Obama said the hacking "could only have been directed by the highest levels of the Russian government," a contention the U.S. has used to suggest Putin was personally involved.

Although the White House announced at the same time it was kicking out Russian officials and closing facilities, it said those were responses to other troubling Russian behavior: harassment of U.S. diplomats by Russian personnel and police.

The 35 Russian diplomats being kicked out are intelligence operatives, Obama said. They were declared "persona non grata," and they were given 72 hours to leave the country. The State Department declined to identify them.

The two compounds being closed down are recreational facilities owned by Russia's government, one in Maryland and one in New York, the U.S. said. The White House said Russia had been notified that Russia would be denied access to the sites starting noon on Friday.

Russian officials have denied the Obama administration's accusation that the Russian government was involved at the highest levels in trying to influence the U.S. presidential election. U.S. intelligence agencies concluded that Russia's goal was to help Trump win - an assessment Trump has dismissed as ridiculous.