BEIJING (Reuters) - The United States should not block Chinese acquisitions of U.S. semiconductor technologies, a leading state think-tank in Beijing said on Wednesday, as Washington heightens scrutiny of Chinese investments in the sector.

FILE PHOTO - The headquarters of German chip equipment maker Aixtron SE is pictured through a security fence in Herzogenrath near the western German city of Aachen, October 25, 2016. REUTERS/Wolfgang Rattay

Acquisitions and joint ventures are becoming more difficult for Chinese firms, Hu Zhijian, president of the Chinese Academy of Science and Technology for Development (CASTED), told reporters in Beijing on Wednesday.

“It is not wise for the U.S. to close its doors in industries that are declining in profit ... the United States should step forward and develop new technology areas,” said Hu.

U.S. regulators have called for heightened scrutiny of Chinese chip acquisitions leading to a chill in overseas M&A activity by Chinese chip firms, with a number of high-level deals failing to gain approval.

In December the Obama administration blocked China's Fujian Grand Chip Investment Fund (FGC) from completing the acquisition of German semiconductor firm Aixtron AIXGn.DE over national security concerns related to Aixtron's U.S. assets.

In March China-backed buyout fund Canyon Bridge Capital Partners LLC resubmitted a $1.3 billion bid for U.S. chip firm Lattice Semiconductor Corp LSCC.O to the Committee on Foreign Investment in the United States (CFIUS) after the initial review period expired.

More than 20 U.S. Congress members signed a letter to the U.S. Treasury in December calling for a block on the Lattice deal, saying it could disrupt the U.S. military supply chain and increase reliance on foreign chipmakers.

“The United States should not be afraid of other countries catching up,” Hu said, adding that China is seeking technologies the United States has already developed in the past two decades and Chinese investment could boot profitability in the sector.

Washington recently sought to strengthen the role of CFIUS, the inter-agency committee that reviews foreign acquisitions of U.S. companies on national security grounds.

U.S. politicians and lawmakers have called for the committee to increase deal scrutiny in areas where China is seeking to build world-leading technology, including artificial intelligence.

China will release a national artificial intelligence plan in the coming months, following a similar roadmap released by the United States, Hu said.