Hong Kong (CNN Business) Huawei secretly helped build North Korea's cell phone network, potentially in violation of sanctions aimed at pressuring the regime to stop developing nuclear weapons, according to a report by The Washington Post.

Citing documents leaked by a former employeeand people familiar with the arrangement, the Post reported on Monday that Huawei worked with China's state-owned Panda International Information Technology on a variety of telecommunications projects in North Korea for at least eight years until 2016.

According to past work orders, contracts and spreadsheets provided to the Post, Huawei and Panda International transported equipment such as base stations and antennas to North Korea to help the country build its 3G network, the newspaper reported.

"This is how many North Koreans were using their phones. This was done in secret. They used code names to avoid saying North Korea," said Washington Post writer, John Hudson, in an interview with CNN.

The documents show Huawei used a code — A9 — when referring to North Korea,according to the Post.

Huawei is the world's largest telecommunications equipment maker and a leading smartphone brand . The Chinese company has been under pressure from a US campaign to prevent the use of its equipment in the roll out of 5G networks on national security grounds. Huawei denies that any of its products pose a national security risk.

In a statement responding to the Post report, Huawei told CNN that it has "no business presence" in North Korea.

The company said that it complies "with all applicable laws and regulations in the countries and regions where we operate, including all export control and sanction laws and regulations of the UN, US and EU."

A company spokeswoman declined to comment on whether Huawei has done business in the past in North Korea. She also declined to comment on whether the company disputes the Post's extensive report.

the national security or foreign policy interests of the United States. The blacklist prevents US companies from selling tech and supplies to Huawei. In May, the US government added Huawei to a trade blacklist , saying it had reason to believe that Huawei had been involved in activities contrary tothe national security or foreign policy interests of the United States. The blacklist prevents US companies from selling tech and supplies to Huawei.

Washington has long suspected Huawei of skirting US sanctions on certain countries. In January, the Department of Justice charged Huawei with violating sanctions on Iran , stating in court documents that the company had been under investigation for violating US export laws since at least 2007. Huawei has pleaded not guilty.

Separately, the Commerce Department reportedly subpoenaed Huawei in 2016, demanding the company turn over information regarding the export or re-export of American technology to North Korea. The Commerce Department declined to comment on the latest allegations.

In 2014, the Commerce Department [Chinese] People's Liberation Army and/or to export items to destinations sanctioned by the United States." Repeated calls to Panda International went unanswered.In 2014, the Commerce Department added Panda International to a trade blacklist, saying the company "attempted to supply items to the[Chinese] People's Liberation Army and/or to export items to destinations sanctioned by the United States."

Asked by reporters about Huawei's relationship with North Korea on Monday, President Donald Trump said, "We'll have to find out. Our relationship with North Korea's been very good."

The revelation that Huawei potentially violated US sanctions on North Korea could complicate Trump's current stance on the Chinese company.

Last month, the US president said he would ease some restrictions on Huawei, saying he would allow American firms to resume sales to Huawei of products that don't pose a security threat.

Following the Post report, Republican and Democratic lawmakers renewed demands for a tougher stance on Huawei.

Democratic Sen. Chris Van Hollen and Republican Sen. Tom Cotton urged Trump to impose orders banning the export of US parts and components to Chinese telecommunications companies like Huawei that violate US export control or sanctions laws.

The United States needs to make it clear "that any company that does business with North Korea — like Huawei reportedly did — will face American sanctions," the senators said in a statement.