Putin said Sunday that the cut will make the size of the U.S. diplomatic mission in his country equal to that of Russia's diplomatic corps in the U.S.
"The personnel of the U.S. diplomatic missions in Russia will be cut by 755 people and will now equal the number of the Russian diplomatic personnel in the United States, 455 people on each side," Putin said in an interview on the Rossiya 1 network.
"Because over a thousand employees, diplomats and technical personnel have been working and are still working in Russia, and 755 of them will have to cease their work in the Russian Federation. It’s considerable," Putin said.
A State Department official called the move a "regrettable and uncalled for act."
"We are assessing the impact of such a limitation and how we will respond to it." the official said. "We have no further comment at this time.”
Putin's comments come on the same day that the Kremlin's deputy foreign minister said on ABC News' "This Week" that Russian retaliation over U.S. sanctions is "long, long overdue."
Deputy Foreign Minister Sergei Ryabkov talked to "This Week" co-anchor Martha Raddatz about the Kremlin's action Friday demanding a cut in the number of American diplomats in Russia and seizing two U.S. facilities.
"I think this retaliation is long, long overdue," Ryabkov said.
The Russian Foreign Ministry announced Friday that the size of the U.S. diplomatic corps was being reduced to 455 but did not specify the size of the cut in U.S. staff.
Ryabkov said Sunday that the Kremlin decided to act after Congress approved a new sanctions bill targeted at Russia as well as North Korea and Iran.
When the U.S. Senate on Thursday "voted so overwhelmingly on a completely weird and unacceptable piece of legislation, it was the last drop," he said.
The new sanctions bill cleared Congress with overwhelming bipartisan support, by a 98-2 vote in the Senate and 419-3 in the House. The legislation now awaits President Trump's signature, and in a statement Friday night the White House said Trump "approves the bill and intends to sign it."
Putin promised last week to retaliate if the United States issued new sanctions, saying, according to Reuters, "We are exercising restraint and patience, but at some moment we'll have to retaliate."
If Trump signs the new sanctions bill, it will be only the latest penalties imposed by the U.S. on Russia.
Former President Obama in late December expelled 35 Russian intelligence operatives and sanctioned five Russian entities and four individuals for an alleged cyberassault on Democratic political organizations during the 2016 presidential campaign. The U.S. also shut down two Russian compounds, in Maryland and New York, that American officials said were used by Russian personnel for intelligence-related purposes.
Those sanctions come on top of penalties that the United States imposed on Moscow in 2014 after Russian troops seized Crimea from Ukraine, sparking the most serious crisis between Moscow and Washington since the end of the Cold War.
Obama broadened those sanctions after Moscow launched a covert war in eastern Ukraine, where the Kremlin has been arming pro-Russian separatists. The European Union also imposed its own sanctions against Moscow over the crisis in Ukraine.
ABC News' Conor Finnegan contributed to this report.