President Obama's administration announced sweeping new measures against Russia on Thursday in retaliation for what U.S. officials have characterized as interference in this fall's presidential election, ordering the expulsion of Russian "intelligence operatives" and slapping new sanctions on state agencies and individuals suspected in the hacks of U.S. computer systems.

The response, unveiled just weeks before President Obama leaves office, culminates months of internal debate over how to react to Russia's election-year provocations.

In recent months, the FBI and CIA have concluded that Russia intervened repeatedly in the 2016 election, leaking damaging information in an attempt to undermine the electoral process and help Donald Trump take the White House.

Because Thursday's announcement is an executive action, it can be undone by the next administration. But Obama's last-minute measures put pressure on Trump, who has largely waved off the allegations against Russia, to make a decision about whether to keep the punitive measures in place.

In a statement issued by his transition office late Thursday, Trump was noncommittal, saying, "It's time for our country to move on to bigger and better things."

"Nevertheless," he said, "in the interest of our country and its great people, I will meet with leaders of the intelligence community next week in order to be updated on the facts of this situation."

Taken together, the sanctions and expulsions announced Thursday were the most far-reaching U.S. response to Russian activities since the end of the Cold War, and the most specific related to Russian hacking. The administration also released a listing of addresses of computers linked to the Russian cyberattacks and samples of malware inserted into U.S. systems.

Several lawmakers have called on the administration for months to respond, saying that tougher measures need to be taken to punish Russia. The White House resisted acting ahead of the election for fear of appearing partisan.

Obama, who had promised a tough U.S. response, said the new actions were "a necessary and appropriate response to efforts to harm U.S. interests." He said Americans should be "alarmed" by an array of Russian moves, including interference in the election and harassment of U.S. diplomats overseas.

"Such activities have consequences," the president said in a statement.

The new measures include sanctions on two Russian intelligence agencies, three companies that are believed to have provided support for government cyber operations, and four Russian cyber officials. The two agencies named are the GRU, Russia's military spy service, and the FSB, the civilian spy agency that grew out of the KGB.

The administration has also ordered 35 Russian operatives to leave the United States and will shut down Russian-owned facilities on Maryland's Eastern Shore and on Long Island in New York believed to have been used for intelligence purposes.

State Department spokesman Mark Toner said the diplomatic retaliation was partly a response to Russian provocations against American personnel in Russia, including "arbitrary police stops, physical assault, and the broadcast on State TV of personal details about our personnel that put them at risk."

In June, a senior U.S. diplomat was attacked by a Russian soldier at the doorway to the U.S. embassy as he tried to enter. That incident, circulated on video, resulted in the earlier expulsion of two Russian diplomats from Washington.

The State Department also said that personal details about U.S. diplomats were publicly released in Moscow, and that the Russian government had refused to approve security upgrades to the U.S. diplomatic facility in St. Petersburg.

Obama suggested Thursday that the United States may undertake covert activity in response to Russian activities. Officials gave no details. The Treasury Department also designated two Russian hackers, Evgeny Bogachev and Aleksey Belan, for criminal cyber activities involving U.S. firms and unrelated to the election hacks.

Moscow, which has denied involvement in attacks related to the election, vowed to respond in kind.

"I cannot say now what the response will be, although, as we know, there is no alternative here to the principle of reciprocity," Russian presidential spokesman Dmitri Peskov said in a statement late Thursday evening carried by the Interfax news service.