Washington (CNN) The US imposed sanctions Thursday against China's military for its purchases of Russian military equipment in a move US officials said is meant to punish Moscow for its "malign activities," including attacks on American elections.

"Today's actions are not intended to undermine the military capabilities or combat readiness of any country," the State Department said in a statement, "but rather to impose costs on Russia in response to its interference in the United States election process, its unacceptable behavior in eastern Ukraine, and other malign activities."

The penalties were applied under a law that requires the US to sanction anyone undertaking significant transactions with certain people affiliated with Russian intelligence and military services, including arms manufacturers. Secretary of State Mike Pompeo also expanded that blacklist Thursday, adding the names of 33 Russians to bring the total roster to 72 people.

Pompeo, in consultation with Treasury Secretary Stephen Mnuchin, imposed sanctions on the Chinese military's Equipment Development Department and its director, Li Shangfu, for purchasing Su-35 combat aircraft and a S-400 surface-to-air missile system from Russia.

"This is a significant step," a senior administration official told reporters. The official said it was the first time anyone has been sanctioned for doing business with people on the blacklist of Russian operatives.

Russian S-400 Triumph medium-range and long-range surface-to-air missile systems ride through Red Square during the Victory Day military parade in Moscow on May 9, 2017.

That list is mandated by the Countering America's Adversaries Through Sanctions Act, passed by Congress amid concern that President Donald Trump would not take tough action against Russia and could even move to ease sanctions on Moscow.

The official was unable to say how much the Chinese company had spent on the Russian equipment, but said deliveries had taken place in December and January.

The goal of expanding the blacklist, the administration official said, was to make people "think twice" about doing business with anyone on it. "We hope (it) will be a signal to avoid to doing business with these people," the official said.

Chinese Foreign Ministry Spokesman Geng Shuang said Friday Beijing "expresses its indignation" over the sanctions, and was already in "solemn negotiation" with Washington.

"(The sanctions) have severely violated the basic norms of international relations and damaged the relations between the two countries and two militaries," Geng said at a daily press conference.

"We strongly urge the US side to correct the mistakes immediately and revoke the so-called sanctions. Otherwise the US has to bear the consequences of it."

Expanded blacklist adds Russians

The newly expanded blacklist includes the 25 Russian nationals who were indicted by special counsel Robert Mueller for interfering in the 2016 presidential election by hacking Democratic targets and spreading propaganda on social media. The State Department announcement said all of these individuals are involved in the "intelligence sector" of the Russian government.

This includes the Russian troll farm known as the Internet Research Agency and its patron, Yevgeny Prigozhin, an oligarch who has close ties to Russian President Vladimir Putin. Prigozhin has ridiculed the criminal charges and is unlikely ever to enter a US courtroom.

The US also blacklisted the director of the Russian military intelligence agency known as the GRU and a dozen GRU officers who were indicted in June for allegedly hacking the Democratic National Committee and Hillary Clinton's campaign chairman in 2016. Private emails from both targets were published by WikiLeaks before the election, roiling the race and giving Trump's campaign a boost.

A senior administration official stressed that the blacklist "is not itself a sanctions imposition; nothing specifically happens to someone by virtue of being on that list" but it is meant to signal that "if anyone else engages in a significant transition" with people on the list, they could face sanctions.

Earlier this year the Treasury Department sanctioned the Russian nationals indicted by the special counsel, barring US citizens from doing business with them. The State Department's step Thursday raises the prospect that foreigners might also face penalties for engaging with those on the list.

The people on the blacklist will likely remain in Russia, where they have safe haven and won't be extradited to the US, so the Treasury sanctions and State blacklists are likely the only punishment they'll face from US authorities.

Since Russia is the world's second largest weapons seller, after the US, the law raised the awkward prospect that Washington could be in the position of sanctioning allies who buy military equipment from Moscow.

The client list of these blacklisted Russian entities includes US counterterrorism partners such as Morocco, Algeria, the United Arab Emirates and Egypt. Qatar is a Russian customer, as well as crucial NATO ally Turkey. Turkish President Recep Tayyip Erdogan said Aug. 31 that his country will purchase the S-400 system as soon as possible.

The senior administration official said the US would distinguish between small sales and major purchases as it considered whether to apply sanctions.

"We are not targeting things such as simply the provision of spare parts and maintenance," the official said, adding that the administration would focus on "much bigger ticket items" that make for a "significant qualitative change in the nature of equipment shipped abroad."

The official said the Countering America's Adversaries Through Sanctions Act had had the effect of delaying "several billion dollars' worth of arms transfers" from Russia to other countries, "but since China has now gone ahead and done what is clearly a significant transaction ... we feel it necessary and indeed are required by the law to take this step today."