WASHINGTON — President Obama struck back at Russia on Thursday for its efforts to influence the 2016 election, ejecting 35 suspected Russian intelligence operatives from the United States and imposing sanctions on Russia’s two leading intelligence services.

The administration also penalized four top officers of one of those services, the powerful military intelligence unit known as the G.R.U.
Intelligence agencies have concluded that the G.R.U. ordered the attacks on the Democratic National Committee and other political organizations, with the approval of the Kremlin, and ultimately enabled the publication of the emails it harvested to benefit Donald J. Trump’s campaign.

The expulsion of the 35 Russians, who the administration said were spies posing as diplomats and other officials, and their families was in response to the harassment of American diplomats in Russia, State Department officials said. It was unclear if they were involved in the hacking.

In addition, the State Department announced the closing of two waterfront estates — one in Upper Brookville, N.Y., and another on Maryland’s Eastern Shore — that it said were used for Russian intelligence activities, although officials declined to say whether they were specifically used in the election-related hacks.