Journalists covering President Donald Trump's meeting with North Korean leader Kim Jong Un in Singapore this week were given free USB-powered fans as a gift.

Security experts say anyone who plugs the fans in is at risk of getting hacked.

Journalists covering this week's summit between President Donald Trump and North Korean leader Kim Jong Un in Singapore were given a fun gift bag containing a water bottle, a trial to the Straits Times newspaper, and a tourism guide to the island where the leaders' meeting took place.

It also included a tiny fan that plugs into a mini-USB port or iPhone Lightning port for power, according to tweets from the historic summit.

It could be a nice gesture from the hosts. As the Dutch journalist Harald Doornbos wrote in a tweet about the fan, "it is pretty hot here in Singapore," according to a translation from the BBC.

But security experts around the web warned that the fan may not just be a way to stay cool. It could be a Trojan horse designed to steal data from any journalist who plugged the fan into his or her device.

Anything that plugs into a USB port could allow an attacker to get malicious software onto your computer. It's how the notorious Stuxnet worm infected its targets, and many big companies worried about information security forbid their employees from plugging anything into a USB port.

Twitter exploded with security experts telling journalists not to plug the fan in. It could install keylogger software, or hack their email, they warned:

North Korea has become a hacking superpower in recent years, according to The Wall Street Journal. The country has been linked to attacks like the "Wannacry" ransomware. But North Korea has no known connection to the fans, according to the BBC.

Of course, the USB fan could just be that — a way to stay cool at a hot summit. But it's probably not worth the risk to find out.