The first big test of Joe Biden’s lofty clean-power ambitions may not be congressional approval of sweeping climate legislation, but managing a solar supply chain that’s being shaken by the seizure of imported Chinese panels.

Multiple companies have now had solar components detained at U.S. ports in the aftermath of a Biden administration ban on equipment using raw materials originally from Hoshine Silicon Industry Co., according to people familiar with the situation who asked for anonymity while discussing sensitive trade issues.

The seizures come amid a new push by some U.S. solar manufacturers to extend tariffs to China-linked factories in Vietnam, Malaysia and Thailand, the largest panel suppliers for the U.S. Together the developments threaten to disrupt the U.S. solar market, potentially jeopardizing Biden’s goal of a carbon-free power sector by 2035.