The US International Trade Commission began investigating whether the US smartphone maker Blu infringed standard patents of LG Electronics’ Long Term Evolution, according to the independent federal agency.

Blu, established in 2009, is the sixth-largest handset maker in the North American market, selling low-end phones worth below $300. The firm sold around 5.2 million units last year -- a 68 percent growth from the previous year.

LG Electronics is the third-largest handset maker in the US, with around 13 percent market share, following Apple and Samsung.

“The US International Trade Commission has voted to institute an investigation of certain LTE wireless communication devices and components. The products at issue include mobile phones,” the ITC said in a statement released last week, adding the investigation is based on a complaint filed by LG Electronics.

In March, LG Electronics filed the complaint with the ITC, seeking a cease-and-desist order and claiming Blu imported smartphones that infringe five of LG’s LTE standard patents. The Korean tech firm also filed an infringement lawsuit and claimed compensation against Blu in a Delaware federal court.

These are the first complaints LG has filed against another smartphone maker.

“This blatant disregard for the intellectual property rights of (LG) is consistent with Blu Products’ current practice of paying no one licensing fees,” LG wrote in its ITC complaint, adding that Blu’s “conduct of unfair competition has and will continue to adversely affect” the company.