The United States International Trade Commission said on Thursday it launched a patent probe into Huawei Technologies Co Ltd and ZTE Corp -- the second investigation into Chinese telecom equipment makers since August.

The U.S. International Trade Commission on Thursday initiated a Section 337 investigation into wireless devices from Chinese communications companies Huawei and ZTE for patent infringement.

The investigation will focus on certain wireless devices with 3G and 4G capabilities and components, according to a statement posted on the commission's website.

Four companies -- Samsung Electronics Co Ltd, Nokia Corp, Huawei and ZTE -- are involved in the investigation, it said.

The products being investigated include smartphones, tablets and laptops, the statement said. In August, the two Chinese telecom companies faced a similar investigation launched by the commission, but the case has yet to reach its final decision.

If Huawei and ZTE are found guilty of patent violations, the products being investigated will be banned from the US market.

"ZTE is aware of this investigation and we are preparing to respond to the suit," ZTE said in an e-mail. "We hope to seek reasonable solutions based on the rules of mutual respect and mutual benefits."

Zhou Shijian, a senior trade expert at Tsinghua University, said Chinese companies should learn to protect themselves from potential trade conflicts.

"We have seen that more and more US investigations now happen in the high-tech and green-energy sectors," Zhou said.

"This demonstrates that Chinese high-tech companies are moving closer to their US peers and have started to impose pressure on them," Zhou said, adding that similar investigations from the US are inevitable, as it hopes to protect its own interests.

Huawei and ZTE should try to prove that they did not violate patent rights, he said.

"In the long run, Chinese companies have to pay more attention to innovation in order to gain an advantage."