NEW YORK  - US intelligence agencies hacked into the email servers of Chinese tech giant Huawei five years ago, two publications reported Monday.

They said the action was taken around the time concerns were growing in Washington that the telecommunications equipment manufacturer was a threat to US national security.

The National Security Agency (NSA) began targeting Huawei in early 2009 and quickly succeeded in gaining access to the company’s client lists and email archive, according to German weekly Der Spiegel, citing secret US intelligence documents leaked by former NSA contractor Edward Snowden. The New York Times also published the documents.  Huawei objects to activities that threaten network security, said William Plummer, the company’s vice president of external affairs.

“Huawei has declared its willingness to work with governments, industry stakeholders and customers in an open and transparent manner, to jointly address the global challenges of network security and data integrity,” Plummer said in an email. “The information presented in Der Spiegel and the New York Times article reaffirms the need for all companies to be vigilant at all times.” Among the people whose emails the NSA was able to read were Huawei president Ren Zhengfei, Der Spiegel said.

Meanwhile, former US President Jimmy Carter says he believes the National Security Agency is probably monitoring his email.

In an interview with NBC television, a leading American network, Carter said he favours snail mail when communicating with foreign officials. “[The justification for surveillance] has been extremely liberalized and, I think, abused by our own intelligence agencies,” Carter said on Sunday’s “Meet the Press” news programme. 

“As a matter of fact, you know, I have felt that my own communications are probably monitored. And when I want to communicate with a foreign leader privately, I type or write the letter myself, put it in the post office, and mail it.”

“Old fashioned snail mail,” the journalist interviewing him remarked. “Yeah. Because I believe if I send an email it will be monitored,” he said.

Carter has previously expressed support for Edward Snowden, the former government contractor who leaked documents on the NSA’s controversial surveillance programmes.

“He’s obviously violated the laws of America, for which he’s responsible, but I think the invasion of human rights and American privacy has gone too far,” Carter said in an interview with CNN last June. “I think that the secrecy that has been surrounding this invasion of privacy has been excessive, so I think that the bringing of it to the public notice has probably been, in the long term, beneficial.”

The former president later said the United States’ democracy had been compromised by the spying.

“America does not at the moment have a functioning democracy,” Carter said at an event in Atlanta in July.