The US government is investigating Chinese telecom companies ZTE and Huawei as it seeks to assess potential threats posed by the duo’s expansion into the American market, according to an article from PC World.

The equipment makers, who have grown out of China to hold significant business interests across the world, are being scrutinised by a House Intelligence Committee that is looking into whether either firms’ products could be used to aid espionage and cyber-spying.

In announcing the investigation, US Representative Mike Roger said:

The fact that our critical infrastructure could be used against us is of serious concern.

Since establishing its US operations in 2001, Huawei has won contracts with more than 25 in the country, including Leap, Alltel and XO. ZTE is a newer arrival, having set up shop in the US telecom market, which is one of 160 markets where it is active, in 2004.

News of the investigation comes just weeks after Huawei issued a strong denial in response to claims that its equipment was being used to track and monitor movements of citizens in Iran.

The US has been on alert with regard to spying over the Internet after details of a China-led cyber espionage campaign that laster six months and targeted almost 50 US companies were released this month. The attacks targeted a range of human rights NGOs, automotive companies and chemical firms in the US through the sending of infected emails and malicious software.

Just last month, the Japanese government admitted that it had suffered an attack which it had traced back to China. Computers and servers in the lower house of the country’s parliament building were compromised in an attack in July.