UPDATE 1-US House panel opens probe into suspected Chinese hacking of Commerce, State emails

(Adds background, attempts to reach U.S. government officials, China's response, paragraphs 4-10)

By David Shepardson

WASHINGTON, Aug 2 (Reuters) - The U.S. House of Representatives Oversight Committee said on Wednesday it is opening an investigation into China's suspected involvement in recent breaches of Commerce and State department email systems.

Representative James Comer, who chairs the committee, and the heads of two subcommittees asked Commerce Secretary Gina Raimondo and Secretary of State Antony Blinken for staff briefings by Aug. 9.

"We are also concerned that this attack on federal agencies, including the email account of a senior U.S. government official such as yourself, reflects a new level of skill and sophistication from China’s hackers," the lawmakers wrote Raimondo.

Raimondo was among a group of senior U.S. officials whose emails were hacked earlier this year by a group Microsoft said was based in China, according to a person briefed on the matter. The State and Commerce departments did not immediately return messages seeking comment.

Last month's news that Chinese hackers penetrated the emails of senior State and Commerce department officials caused a stir amid high tensions between Beijing and Washington over a host of issues, from trade to Taiwan.

The full extent of the breach, which affected at least two dozen other organizations, is not clear. The Wall Street Journal reported last month that the hackers also accessed the email account of the U.S. ambassador to China as well as Daniel Kritenbrink, the assistant secretary of state for East Asia.

Hundreds of thousands of emails were stolen overall, the Journal said.

Raimondo said last month she still plans to visit China later this year despite the reported Chinese hacking. "We're planning the trip now, which doesn't mean that we excuse any kind of hacking or infringement on our security," Raimondo told CNBC.

China's embassy in Washington said in an earlier statement that identifying the source of cyber attacks was complex and warned against "groundless speculations and allegations." (Reporting by David Shepardson in Washington Editing by Jonathan Oatis and Matthew Lewis)