By Greg Roumeliotis

(Reuters) - A U.S. national security panel's unusual decision to review Singapore-based Broadcom Ltd's <AVGO.O> $117 billion hostile bid for smartphone chipmaker Qualcomm Ltd <QCOM.O> illustrates an expanding focus on the competitiveness of the U.S. semiconductor industry amid advances by China, regulatory experts said.

The secretive panel, called the Committee on Foreign Investment in the United States (CFIUS), has scuppered several attempts by Chinese technology companies to acquire U.S. chipmakers in the last 12 months over concerns about the transfer of potentially sensitive technology.

Broadcom is not a Chinese company, and has pledged to move its domicile from Singapore to the United States, arguing this will makes its acquisition of Qualcomm not covered by CFIUS. However, many of Qualcomm's rivals, including Huawei Technologies Co Ltd [HWT.UL], are Chinese.

Huawei is forging closer commercial ties with big telecommunication operators across Asia, the Americas and Europe, putting the company in prime position to lead the global race for wireless 5G networks, despite U.S. allegations it poses a security threat.

CFIUS views Qualcomm as a prized U.S. asset in the development of 5G wireless technology, which allows for the transmission of data at very fast speeds. It wants to make sure Qualcomm does not lose its status as a dominant player in wireless chip technology, according to a source familiar with the panel's thinking.

As a result, Broadcom's business plan for Qualcomm, including any divestitures it plans in order to appease antitrust regulators, will be scrutinized by CFIUS, lawyers who advised companies on their CFIUS applications said.

"This shows how indirect exposure to China is a frequent, but under-noticed, source of perceived national security risk," said Mario Mancuso, a former CFIUS member who is now a partner at law firm Kirkland & Ellis LLP.

CFIUS' stance has toughened as U.S. President Donald Trump seeks to pressure China to help tackle North Korea’s nuclear ambitions and be more accommodative on trade and foreign exchange issues.

Unfilled political vacancies in several government departments and agencies have also made it harder for CFIUS to approve deals.

Canyon Bridge Capital Partners LLC, a U.S.-based private equity firm funded by the Chinese government, saw its $1.3 billion acquisition of U.S. chipmaker Lattice Semiconductor Corp <LSCC.O> collapse last year after it was blocked by CFIUS, a rejection subsequently upheld by Trump.