By Sijia Jiang

HONG KONG (Reuters) - Chinese telecoms equipment maker Huawei is reviewing its relationship with FedEx Corp after it claimed the U.S. package delivery company, without detailed explanation, diverted two parcels destined for Huawei addresses in Asia to the United States and attempted to reroute two others.

Huawei told Reuters on Friday that FedEx diverted two packages sent from Japan and addressed to Huawei in China to the United States, and attempted to divert two more packages sent from Vietnam to Huawei offices elsewhere in Asia, all without authorization, providing images of FedEx tracking records.

Reuters could not verify the authenticity of the records. Shown the images of the tracking records, FedEx declined to make any comment, saying company policy prevented it from disclosing customer information.

Huawei said the four packages only contained documents and "no technology," which Reuters was unable to independently confirm.

Huawei declined to elaborate on why it thought the packages were diverted.

"The recent experiences where important commercial documents sent via FedEx were not delivered to their destination, and instead were either diverted to, or were requested to be diverted to, FedEx in the United States, undermines our confidence," Joe Kelly, a spokesman for Huawei, told Reuters.

"We will now have to review our logistics and document delivery support requirements as a direct result of these incidents," the spokesman said.

Huawei acknowledged to Reuters that one package originating in Vietnam was received by Friday, and the other was on its way, according to FedEx tracking records provided by Huawei.

FedEx spokeswoman Maury Donahue told Reuters the packages were "misrouted in error". She acknowledged in an earlier statement that the U.S. Department of Commerce had recently added Chinese companies and affiliates to its "Entity List", but did not elaborate.

FedEx was not requested to divert the packages by any other party, she added.

"This is an isolated issue limited to a very small number of packages," said FedEx, referring to the four parcels affected. "We are aware of all shipments at issue and are working directly with our customers to return the packages to their possession."

FedEx China on Tuesday apologized on its Chinese social media account for the "mishandling" of Huawei packages and confirmed there was no "external pressure" to divert packages.

The U.S. Department of Commerce did not reply to a request for comment on whether the incident might be related to its move on May 16 to add Huawei to the so-called "Entity List," preventing it buying certain items from U.S. companies without U.S. government approval.

FORMAL COMPLAINT

The United States believes Huawei, the world's largest telecom network gear maker leading the way in creating the next generation of wireless networks known as 5G, is a potential espionage threat because of its close ties with the Chinese government.

Huawei has repeatedly denied it is controlled by the Chinese government, military or intelligence services.

The issue has become a flashpoint in an escalating trade battle between the world's two biggest economies.

The two packages sent on May 19 and May 20 from Tokyo, intended for Huawei in China, ended up in Memphis, Tennessee, the headquarters of the U.S. company, by May 23, according to images of FedEx tracking records shown to Reuters by Huawei.

The two packages originating from Hanoi on May 17, destined for Huawei's Hong Kong and Singapore offices, were held up after arriving in local FedEx stations in Hong Kong and Singapore on May 21 for "delivery exception," according to other images Huawei showed Reuters.

According to FedEx's website, the status "exception" means an unexpected event is preventing delivery of a package, for example a customs delay, a holiday, or no one being available to accept delivery. FedEx declined to give details on what the exception was in this case.

According to Huawei, a FedEx customer service representative in Vietnam replied to their inquiry on May 22 when two expected packages did not arrive on time, saying: "Please be informed that FDX SG received notification from FDX US to hold and return the package to US. Hence, the shipment is not deliver to consignee and now being hold at FDX station and under process to RTS it (return to sender)," the representative wrote in broken English, according to an email Huawei showed to Reuters.

Huawei told Reuters that both Vietnam packages were sent by its shipping agent, a contractor to Huawei whom it did not identify, and contained urgent documents. It said the shipping agent refused permission for FedEx to send the packages to the United States and instructed they be returned, Huawei told Reuters. Reuters could not confirm that.

Huawei told Reuters it only learned that the Japan-originated packages, which were sent by suppliers that it did not identify, had been diverted to the United States after checking FedEx's tracking record.

The company said it has lodged a formal complaint with China's postal regulator, which it said is investigating the incident. China's State Postal Bureau did not return a request for comment.

(Reporting by Sijia Jiang in Hong Kong; Additional reporting by Lisa Baertlein in Los Angeles, James Pearson in Hanoi, Ankit Ajmera in Bengaluru and Yawen Chen in Beijing; Editing by Bill Rigby)