Chinese networking and telecoms company Huawei has said that the US government must disclose "unsubstantiated" national security concerns about the company.

Huawei external affairs vice-president William Plummer blamed the US government after it took a decision to block the business from building a national emergency communications network, reported the Financial Times.

"Stop the manufactured fear. If you have something to say, substantiate it," said Plummer.

The comments are perhaps the most assertive ones the company has said since 2008, when the US began barring the company from acquiring companies in the country.

In June, Huawei chief legal officer Dr Song Liuping said, "We believe that the misconceptions stem from media and political parties."

In February this year, Huawei’s deputy chairman wrote an open letter to the US government, inviting it to conduct a formal probe, which has not been accepted so far.

Liuping said, "It is a fact that in the US there are a lot of impressions of Huawei that are not in line with the truth."

The company has been cautious to such moves though. Now, however, it is for the first time that the company is demanding answers from the US Department of Commerce after officials blocked it from getting involved in the building of a national wireless emergency communications network.

The Department of Commerce said Huawei would not take part in building the new network due to "US government national security concerns".

In a counter-offensive, Plummer has effectively accused the government of lack of transparency.

"We have seen multiple instances where we are being asked for transparency. Well, the shoe is on the other foot. We would like to see some accountability and transparency associated with this decision. Where is the due process?" said Plummer.

Observers widely believe US officials have not been transparent about their dealings with Huawei.

According to the Financial Times, a recent unclassified US intelligence report obtained by the paper quotes national Chinese media stating that "Huawei’s Sun Yafang, its chairwoman, once worked for the ministry of state security and that she used her ‘connections’ at the ministry to help Huawei through financial difficulties at ‘critical moments’."

Huawei has maintained that its relationship with the Chinese government is professional.

Plummer told the FT that "the intelligence report was ‘just innuendo and suggestion’".

"It is not intelligence. At the very best, it is a Reader’s Digest of media reports," he said.

He also accused the US government of double standards, saying that it was "ironic" that the commerce department was seeking to block Huawei at the same time that the US government was trying to encourage foreign investment, according to the FT.

Earlier, when the company had a more toned down approach to its problems in the US, Huawei had said that it has an open attitude to address security concerns of the US government, and also that it aims to popularise its brands in the West to gain credibility among governments.

Huawei chief legal officer Dr Song Liuping had said in June: "Huawei is taking an open and transparent attitude to address the concerns of the US government. In fact we have been making all efforts to address their concerns and questions."

The multinational networking and telecommunications equipment company headquartered in Shenzhen, Huawei was founded in 1988 by Ren Zhengfei, who is a Communist party member.

Twenty eight years ago, Zhengfei retired as a deputy director in the People’s Liberation Army’s Engineering Corps.

Huawei had to face several accusations in the past including one which claimed that the company had supplied equipment to Iran, Saddam Hussein and the Taliban.

Huawei has also come under the scanner of British security officials. However, in June, Huawei told The Telegraph that the company is a "normal commercial institution and nothing more."

It said that in February this year, Huawei’s deputy chairman wrote an open letter to the US government, inviting it to conduct a formal probe, which has not been accepted so far.

Liuping said, "It is a fact that in the US there are a lot of impressions of Huawei that are not in line with the truth."

The company is now concentrating on increasing its R&D on 4G and to popularise its brands.

Liuping said, "We were mainly focused on domestic markets before 2000 because intellectual property is closely related to the territory and we were not selling in the countries where they [competitors] have patents.

"We have been working on accumulating our own intellectual property in the last 15 years that is also valuable to the other firms in the industry."

Recently, John Suffolk, former chief information officer for the UK government, joined Huawei as global cyber security officer.

Suffolk was previously CIO for the UK government, in charge of its G-Cloud initiative – a plan to roll out a shared infrastructure across public sector bodies as part of a multi-billion pound cost reduction programme. His surprise resignation was announced in November 2010 and since his departure he has advised governments on how ICT can be used to transform the public service sector and generate economic growth.

Suffolk’s role will be based at Huawei’s global headquarters in Shenzhen, China.

"Having spent 7 years in Government with the last 5 as the UK Government CIO and CISO, security was a core part of my thinking, planning and execution," Suffolk wrote on his blog.

"We all accept that as technology becomes more pervasive and we become more reliant on technology we need to come together globally to address the challenges and threats posed by those who would wish to exploit any vulnerability in the technology."

"My role will be to ensure that our cyber security assurance system integrates end-to-end cyber security into solutions covering our cloud computing solutions, pipes/ telecommunications and all devices from mobile broadband to PDA’s where appropriate, the customer-oriented business processes and the whole ICT supply chain," he added.