The warning came soon after the United States slapped punishing financial sanctions on a Chinese military unit for its purchase of the S-400 surface-to-air missile as well as the Sukhoi Su-35 fighter jets.
This was the first time the Trump administration targeted a third country with its CAATSA sanctions, designed to punish Russia for its seizure of Crimea and other activities.
The US State Department said it was applying the 2017 legislation against the Equipment Development Department of the Chinese Ministry of Defence. At the same time, the State Department also announced it was placing 33 Russian intelligence and military-linked actors on its sanctions blacklist under the CAATSA rules.
"The ultimate target of these sanctions is Russia," a senior administration official told journalists, insisting on anonymity.
"CAATSA sanctions in this context are not intended to undermine the defense capabilities of any particular country. They are aimed at imposing costs on Russia in response to its malign activities."
However, the sanctions would mean that all property and interests in property within the US jurisdiction of the EDD and Shangfu have been blocked and the US citizens are barred from transacting with them, the official said."We want to stress that the legislative standard here is a significant transaction with an entity that appears on the List of Specified Persons. We took these actions because China took delivery of 10 Sukhoi fighter aircraft, specifically Su-25s, in December of 2017, after the CAATSA statute came into force. It also took delivery of a batch of S-400 sometimes known as SA-21 surface-to-air missile systems or related equipment in January of this year," the official said.
Both these Chinese transactions from Russia, he said, occurred after the CAATSA sanctions statute came into force. The deal was negotiated between the Equipment Development Department and Rosoboronexport, which is Russia's main arms export entity, he added.
He declined to give a specific answer a question whether the US would be taking similar action against countries like India or Turkey that buy or are looking to buy the S-400 missile defense system.
"As to other potential recipients of the S-400, we haven't made any determinations yet with respect to what to do about those, but you can be confident that we have spent an enormous amount of time talking about prospective purchases of things such as S-400s and Sukhois with people all around the world who may have been interested in such things and some who may still be," the official said.
The defence deal with Russia had been a major sticking point during the recent 2+2 dialogue held between India and US recently in Delhi, with Washington signaling that it could give India a waiver considering its old relations with Russia. However, Friday’s sanctions suggest that it has changed its stance.
The official said the Trump administration has made it "very clear" to these countries that these systems like the S-400 are a system of key concern with potential CAATSA implications.