China Monday criticised a US decision to block a Chinese company's purchase of German semiconductor equipment maker Aixtron, saying business should not be politicised.

President Barack Obama blocked the deal by rejecting the inclusion of Aixtron's US unit in it.

The US Treasury Department said the Committee on Foreign Investment in the United States had found that the risks posed by the purchase, which could put sensitive technology with potential military applications in Chinese hands, were too great.

Chinese foreign ministry spokesman Lu Kang said the move to purchase Aixtron was purely market-driven.

"China opposes politicising normal business behaviour or interfering in it in a political way," he told a regular press briefing.

"We hope the US side can stop making groundless accusations to Chinese companies and provide a fair environment and good conditions to Chinese investments."

In a statement Friday the US Treasury said publicly-traded Aixtron SE's expertise in technology which is key to making advanced compound semiconductors used for LED lighting, lasers and solar cells also has military applications.

Washington does not want to see such technology end up in the hands of the Chinese government-backed company which wants to buy Aixtron, Grand Chip Investment.

The Treasury said Aixtron's US business was an important contributor to that technology.

In late October the German government withdrew its initial approval for the 670 million euro ($714 million) takeover after Washington raised security concerns.

Citing German intelligence sources, Handelsblatt daily reported that the US had expressed fears that China could use Aixtron technology to bolster its nuclear programme.

After receiving the information, the German economy ministry said on October 24 that it would reopen its review of the deal.

dly/sm

AIXTRON