Russian President Vladimir Putin slammed the ban as a "politically motivated" ruling that "contradicted" the Olympic Charter.
"There is nothing to reproach the Russian Olympic Committee for and if there is no reproach towards this committee, the country should take part in competitions under its own flag," Putin said.
The head of Russia's anti-doping agency said his country had "no chance" of winning an appeal of the ban, which he described as a tragedy for clean athletes.
It accused Russia of falsifying laboratory doping data handed over earlier this year to investigators probing claims of widespread doping.
Russia can appeal the ban to the Court of Arbitration for Sport, but the head of its RUSADA anti-doping agency, Yuri Ganus, said he doubted it would be successful.
"There is no chance of winning this case in court," Ganus, one of the few critical sports officials inside the country, told AFP.
"This is a tragedy. Clean athletes are seeing their rights limited."
Under the sanctions, Russian sportsmen and women will still be allowed to compete at the Olympics next year but only if they can demonstrate that they were not part of what WADA believes was a state-sponsored system of doping.
Russian government officials will be barred from attending any major events, while the country will lose the right to host, or even bid, for tournaments.
Ganus said the WADA ban was the toughest punishment yet against a nation and urged President Vladimir Putin to intervene.
"We have a president and we are waiting for decisive changes from him," Ganus said.
'This is politics'
While admitting there have been instances of doping, Russian officials say the country is no worse than any other. Some have accused other countries of pursuing the ban to remove Russian athletes from competition.
Prime Minister Dmitry Medvedev said Monday that it was "impossible to deny" that doping had taken place but that those involved had already been punished.
"This is the continuation of this anti-Russian hysteria that has already become chronic," Medvedev was quoted as saying.
Sports Minister Pavel Kolobkov said the ban was politically motivated, adding that Russia had done a lot to clean up sport in coordination with WADA.
"I believe it would be right to turn to the Court of Arbitration for Sport," he told reporters, saying he believed Russia's chances in an appeal were "quite good.”
Many in Russian sports also said the decision was political.
"I have no words. How can you mock athletes who have been preparing all their lives for this?" said Aslanbek Khushtov, who won wrestling gold at the 2008 Beijing Olympics.
"Unfortunately this is politics, I don't smell any sport here," he told state news agency TASS.
The scandal has tainted Russia's sporting reputation since the revelation of large-scale state-sponsored doping aimed at improving its medal performance at the 2014 Winter Olympics in Sochi.
Russian track and field athletes were barred from competing at the 2016 Rio Olympics although Russians competing in other events were allowed to take part.
The ban was widened to include all events at the 2018 Pyeongchang Winter Olympics, though Russian competitors who could prove they were above suspicion were able to compete as neutrals under the Olympic flag.
The heads of several Russian sports federations said Monday they were preparing to send athletes to the 2020 Olympics under a neutral flag.
'A proud Russian'
The country's athletes "must go to the Olympics whatever the situation," said the head of Russia's swimming federation, Vladimir Salnikov.
"Of course we'd prefer that our athletes participate under the Russian flag and hear their national anthem. But the circumstances may be different and no one has the right to deprive innocent athletes of their dreams," he told state news agency RIA Novosti.
Vyacheslav Fetisov, a Soviet-era ice hockey legend and now pro-government lawmaker, denounced what he called the "collective punishment" of Russia's athletes.
"I am a proud Russian. I was proud to represent my country," Fetisov, deputy chairman of the lower house State Duma's sports committee, told AFP.
"I will work tirelessly to get today's athletes the opportunity I had to represent Russia - and be up on that podium. It was one of the great privileges of my life."