Aixtron, the German chip equipment manufacturer, said it would ask President Obama to approve its takeover by a Chinese company in spite of national security concerns raised by a federal review committee.

The move highlights fears that it will become even harder to gain US clearance for cross-border deals, especially those involving Chinese companies, once Donald Trump enters the White House. The incoming president has pledged to punish Beijing for allegedly unfair trade and currency policies.

Aixtron said on Friday it was told by the Committee on Foreign Investments in the US, or Cfius, that it would advise Mr Obama not to approve Aixtron’s takeover by Fujian Grand Chip. It said Cfius had cited “unresolved US national security concerns” related to the planned transaction, and remedies proposed by the parties did not adequately address these concerns. The Obama administration has two weeks to make a final ruling. Germany’s economics ministry also recently reopened a review of the deal, casting a pall over relations between Beijing and Berlin.