The Trump administration has in recent weeks imposed sanctions on a series of entities and individuals linked to Iran's oil industry and nuclear program.

Wednesday's sanctions are aimed at organizations involved in "efforts to help the Iranian regime domestically source the manufacturing of critical materials needed for Tehran's ballistic missile program," according to the US Treasury Department.

"The United States cannot allow Iran to develop intercontinental ballistic missiles," US Treasury Secretary Scott Bessent said in a statement.

Tehran's attempts to produce missiles and components domestically "represents an unacceptable threat to the United States and the stability of the region," he added.

Those sanctioned include three Chinese nationals -- Qin Jinhua, Qin Dehui, and Wang Chao -- who work for a China-based firm which has exported carbon fiber precursor materials to a sanctioned Iranian firm, and another Hong Kong-based company

Wednesday's sanctions come a day after the United States announced fresh sanctions on Iranian oil sales to China, as President Donald Trump's administration continues its "maximum pressure" campaign against Tehran while backing ongoing nuclear talks.

The sanctions follow similar designations in recent weeks, at the same time as Washington and Tehran have stepped up nuclear talks.

The two sides held their fourth round of indirect talks over the weekend, which mark their highest-level contact since the United States in 2018 pulled out of the 2015 nuclear deal.