Moscow residents struggled today against the worst smog in living memory which has enveloped the Russian capital from spreading wildfires. Experts warned the concentration of toxic particles was up to five times higher than safe levels, as the city's iconic landmarks like the Kremlin and golden church cupolas disappeared behind a layer of smoke.The emergencies ministry warned that the wildfires which have sparked the smog were still spreading in central Russia as weather forecasters said Russia's worst heatwave in decades would continue for the next days.The fires have raised concerns about the security of Russia's main nuclear research centre in the still closed city of Sarov, one of the areas worst hit by the blazes and where the emergencies ministry has sent thousands of workers. State aviation committee Rosavitsia said flights from Domodedovo, one of Moscow's main international airports, were disrupted by the smog with several flights diverted to other airports and around 40 flights cancelled. Germany closed its embassy until further notice and advised citizens against non-essential travel to the affected regions while the US State Department asked nationals to seriously review travel plans.