Russian President Vladimir Putin brought and drank from his own mug during an official dinner at the G20 summit in Japan, prompting social media jokes and speculation that the longtime leader suffered from paranoia.

Videos showed Putin, in power for almost twenty years, drinking from a white thermos mug while other leaders drank from regular wine glasses.

"This is because he is constantly drinking tea from that thermos," Putin's spokesman Dmitry Peskov explained to the RIA Novosti news agency.

The Russian president was seen toasting US President Donald Trump with the mug.

Trump drank a dark liquid that appeared to be cola from a wine glass.

Putin bringing his own cup to the international event prompted speculation online that the 66-year-old did not trust anyone.

"If you've seen what I've seen, you'd bring your own cup too," a parody account of the Russian leader, @DarthPutinKGB, wrote on Twitter.

The mug resembled one that Putin has drunk from during his annual hours-long press conferences that has a double-headed eagle, Russia's national symbol, on it.

Putin held several one-on-one meetings, including with Trump and UK Prime Minister Theresa May, on the sidelines of the two-day summit in Osaka that began Friday.