Arsenal duo Henrikh Mkhitaryan and Shkodran Mustafi are also seen in the video, although it is unclear whether the pair took part in inhaling the balloon alongside their teammates.
Markets slip as China-US trade deal joy subsides The two-year yield also fell, but by a narrower margin, touching 2.8028 per cent compared with a USA close of 2.833 per cent. In return, the White House said Xi will buy a "very substantial amount" of US agricultural, energy and industrial products.
Some of the players reportedly collapsed and passed out after inhaling the gas.
Nitrous oxide, also known as laughing gas or "hippy crack", is freely available, although it is technically illegal to sell it for recreational purposes.
The footage is the latest in a series of incidents of top players being linked with nitrous oxide, with Raheem Sterling being warned by Liverpool after footage emerged of him using the substance in 2015.