The State Department says it is telling Congress it will continue to waive sanctions on Iran as part of the 2015 nuclear deal.
"The Chinese side is always opposed to unilateral sanctions, to the frequent implementation of unilateral sanctions, especially when it hurts interests of third parties", foreign ministry spokeswoman Hua Chunying says.
The announcement of new US sanctions came as President Donald Trump extended relief from sanctions linked to Iran's nuclear program, as part of the 2015 worldwide agreement to limit Iranian nuclear activity.
"The Treasury Department is imposing new sanctions on Iranian defense officials, an Iranian entity, and a China-based network that supplied missile-applicable items to a key Iranian defense entity", the Treasury Department said.
"We think (this kind of sanctions) are unhelpful in enhancing mutual trust and unhelpful to the worldwide efforts to solve this issue", Hua says at a regular press briefing.
"The United States continues to waive sanctions as required to continue implementing USA sanctions-lifting commitments in the Joint Comprehensive Plan of Action", the State Department said. At the same time, Trump dispatched Secretary of State Rex Tillerson to issue a scathing critique of Iran in which he also cast doubt that the nuclear deal would achieve its objective of keeping Tehran from developing nuclear weapons. She added that its supporters say "that if the U.S.is blamed for the collapse of this deal it will be hard for the U.S.to get partners back on board".
President Donald Trump has said he's reviewing the deal's future.
The group has increased its activities ahead of Trump's first foreign tour, beginning with a trip to Riyadh and Tel Aviv later this month. But he said that given US commitments under the nuclear deal, "the United States is not pursuing efforts to reduce Iran's sales of crude oil at this time".
Iranians are set to vote Friday in the country's presidential election.
The U.S. also punished another Iranian official it said has been involved in Iran's ballistic missile program, as well as Matin Sanat Nik Andishan, a company based in Iran that the U.S. said helped obtain materials for the ballistic missile program. The U.S. said his network helped produce electronics such as missile guidance for Iran's program.
One of its goals, as former Chief of Staff and Director of Policy Planning at the State Department Jon Finer told the Independent, is to "bring accurate, nonpartisan information about the deal at a time when the focus on Iran policy is increasing and there is widespread disinformation about what is in it and how it is working". It also has clinched bigger deals with trans-Atlantic rivals Airbus and Boeing.