The United States has determined that some Chinese companies are providing non-lethal aid to Russia for use in the Ukraine war and authorities are conveying their concerns to the Chinese government, a source familiar with the matter said on Tuesday.

The source, who spoke on condition of anonymity, said: “What we are seeing is non-lethal military assistance and economic support that falls short of total evasion of sanctions.”

The source gave no further details and Reuters could not independently verify this version.

The United States has warned the Chinese government of the consequences in case China provides arms to Russia for use against Ukraine.

U.S. officials are concerned about the current activity and believe it is “a significantly scaled-down version of the PRC’s initial plan, which was to sell lethal weapons systems for use on the battlefield,” the source said.

It is unclear whether the Chinese government is aware of this activity, according to the source.

U.S. representatives are in contact with Chinese authorities through diplomatic channels, according to the source.