A football given to US President Donald Trump by his Russian counterpart may contain a computer chip capable of sending and receiving data.
The FIFA World Cup replica ball, made by Adidas and sold on its site for US$165, ships with a near-field communication (NFC) chip like the one found on some credit cards, reports Bloomberg.
Vladimir Putin gifted the ball to Mr Trump when the two leaders met in Helsinki.
"I'd check the soccer ball for listening devices and never allow it in the White House," said Senator Lindsay Graham.
"The security screening process that is done for all gifts was done for the soccer ball," White House press secretary Sarah Sanders told Bloomberg, without revealing any more information.
Adidas said the chips can't be used for anything other than accessing football videos and competitions.
"It is not possible to delete or rewrite the encoded parameters," the company says on its website.
A prominent hacker told Bloomberg using a modified NFC chip embedded in a soccer ball would require the US President to fall for "a silly attack" by clicking on dodgy links sent to his phone and ignoring security warnings.
Bloomberg said it couldn't be determined from photographs taken in Helsinki if the ball had been tampered with to insert a more nefarious chip.
Russia's predecessor the USSR and the US regularly used secret listening and recording devices to spy on one another during the Cold War.
Earlier this year, a number of strange devices known as IMSI catchers were found around the White House in Washington, DC. They allow users to scoop up text messages and calls.
The US Department of Homeland Security admitted in April it had no idea who was placing them.
Mr Trump has flip-flopped on whether he accepts the US intelligence community's assessment that Russia interfered with the US 2016 election. His campaign is the subject of a long-running investigation into whether it colluded with foreign agents to tip it in his favour.