Two Russian league matches were postponed on Friday as heavy smog, caused by wildfire, tinderbox conditions, cloaked sweltering Moscow, sparking health fears for players and fans.
Spartak Moscow's home clash with Zenit St Petersburg and the Moscow derby between Dynamo and CSKA were called off as high levels of toxic particles were detected.
However, Spartak said the league's decision had been too hasty, as their game was still two days away.
"A match is usually cancelled on the day, not with two days remaining," said Spartak spokesman Leonid Trakhtenberg.
Earlier on Friday, the Russian Football Union (RFU) moved Wednesday's friendly match with Bulgaria to Saint Petersburg also because of the heavy smog in Moscow.
"It's impossible to play in Moscow under existing conditions. It can be dangerous for the players' health," said RFU chief Sergei Fursenko.
The RFU chief also said the decision to transfer the match to St Petersburg was approved by Bulgarian football federation.
Forecasters warned that the record heatwave was going to continue in the coming days, with little rain forecast and the mercury again expected to hit 38 degrees Celsius (over 100 degrees Fahrenheit) later.
Russia is battling its worst forest fires in modern history with emergency services still struggling to contain the flames.

August, 6, 2010, AFP