Washington’s battle with Huawei is spreading to what seems like every corner of business operations around the globe, and this week that included international courier delivery services as well.

But US carrier FedEx is denying any foul play after packages sent from locations in Asia containing Huawei documents were mysteriously rerouted, with some having a layover in the United States.

Reuters first reported the events, detailing two packages sent last week from Tokyo to Huawei offices in mainland China that somehow ended up at FedEx headquarters in Memphis, Tennessee. Two other packages heading for Huawei offices in Singapore and Hong Kong were held up after arriving at FedEx processing stations in both those cities for “delivery exception.”

FedEx did not provide an explanation for what the “delivery exception” was in this case.

Huawei forwarded an email to Reuters from a FedEx representative in Vietnam that read:

“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].”

A representative from Huawei said that the packages contained only documents and “no technology.” The Chinese company was recently placed on a US export control blacklist, prohibiting US-based companies from engaging in certain business activities with the firm. The Trump administration cited national security concerns for the move.

In response to the rerouting of packages, which Huawei said have now made it to their intended destination or are on their way, the company said that it “will now have to review” its relationship with FedEx.

On Tuesday, FedEx released an apology on Chinese social media saying “we apologize for the small number of Huawei packages that were mistakenly rerouted,” adding: “We confirm that no outside party requested FedEx to reroute these packages.”