Following a meeting between President Donald Trump and Russian Foreign Minister Sergei Lavrov and Russian Ambassador Sergey Kislyak in which only Russian press was allowed to attend, several former intelligence officials have raised the possibility that surveillance equipment may have been smuggled into the White House.

The possibility a Russian bug may have made its way into the White House with the Russian media member was raised by former Deputy CIA Director David S. Cohen, who was asked on Twitter if it was “a good idea” to let a Russian government photographer and their equipment into the Oval Office. Cohen responded to the question by saying, “No, it was not.”

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The photographer who accompanied the Russian diplomats was the official photographer for Lavrov, but also a journalist for Russian state-owned media outlet Tass.

While it may seem brazen for a foreign nation to sneak surveillance equipment into the offices of another nation’s highest political officials, Center for Strategic and International Studies (CSIS) Vice President James Lewis told International Business Times such surveillance efforts are common.

“This is standard practice. Lots of countries do it,” said Lewis, a former officer at the Department of State and Department of Commerce.

Yolonda Smith, the director of Product Management at cybersecurity firm Pwnie Express, told IBT with the accessibility of internet-connected devices including smartphones, a foreign actor wouldn’t have to smuggle or hide listening devices to spy. She said a temporary bug “is definitely in the realm of the possible.”

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Lewis described the devices that could be used to bug an office as “pretty small” and said they can easily be stuck under a table “like a piece of gum.” The devices have technical limitations, including signal range and battery life, but can be effective in providing an ear in areas where potentially sensitive conversations take place.

Smith said that even relatively simple tools like pin and button cameras can collect video and audio, and many include cellular and Wi-Fi radios that can instantly send the feedback over the internet to a file server or website.

Jayson Street, an information security ranger at Pwnie Express, told IBT spy equipment is relatively easy to afford and conceal. “You can find a hidden camera pin on eBay for under $50,” he said. “If you have a budget of hundreds of thousands, can you imagine what kind of things you can find?”

Street even suggested the camera used by the Russian photographer could be used for more than filming and photography. “It could be wired to look for thermal or infrared signals as well, which would be able to help assess what is going on behind those wood panels,” he said, though he noted it’s "a very rare occurrence for a camera of possible or questionable origin to have that kind of access to the Oval Office.”

He suggested an actor may want to use a secondary piece of equipment, such as a camera attachment, to house spying equipment. Street said a battery case or lighting attachment could be equipped with a Pineapple device — a penetration tool that can be used to target insecure wireless connections.

“I would primarily focus on smart TV's in the area with open Wi-Fi or Bluetooth connections,” Street said. “But, printers with wireless interfaces would also be good targets.”

Bugs have been discovered at a number of U.S. agencies, Lewis said, and have originated from a number of nations, not just Russia. Lewis said it is advisable to “always do a sweep after a meeting in any place where you let the Russians, the Chinese or a few other friends pay a visit.”

“The White House employs Technical Surveillance Countermeasures Offices to conduct regular bug sweeps,” Smith said, but noted those sweeps are “point in time assessments” — they may prevent long-term spying efforts, but would not be able to pre-emptively stop a short-term bug.