Fifa has suspended European champions Greece and its member clubs from international competition because of government interference in the sport.
European champions Greece ignored repeated warnings, say Fifa
World governing body Fifa said the Hellenic Football Federation had broken rules on "the independence of members and decision-making in each country".
It means Greek clubs and officials are banned from European competitions.
And it jeopardises Steve McClaren's first game as England boss - a friendly against Greece on 16 August.
The suspension will be in place with "immediate effect and until further notice", according to a Fifa statement.
HFF spokesman Michalis Tsapidis said the federation was shocked at the verdict.
"It is something that was not expected," he said.
"There will be an emergency press conference on Tuesday at our headquarters at midday when our president Mr (Vasilis) Gagatsis will give our official reactions and news of what steps we plan to take.
"Fifa's ruling deals specifically with the independence of the national federation but it is a very complicated issue.
"We, of course, hope for a quick and favourable solution to this problem for the good of Greek football."
Fifa said that it had issued several warnings to the HFF to guarantee, by a 15 July deadline, that the running of football in the country would be free from political involvement - but this had been ignored.
If Greece have been suspended by Fifa, we would want to speak to Fifa and the Greek Federation to clarify the situation
FA spokesman Adrian Bevington
In particular, Fifa cited a proposed new Greek law on professional football leagues in the country that "constitutes another example of interference from the government in football affairs".
Sports Minister George Orfanos drafted the law shortly after the conservatives came to power in 2004, and the Greek FA claim it compromises its independence.
Orfanos had repeatedly publicly pledged to revise the law but never did.
Therefore, the statement added, "the Fifa Emergency Committee has determined that this suspension is necessary".
Orfanos expressed surprise at the ban and said he would seek contact with Fifa president Sepp Blatter on Tuesday.
Orfanos told state-run NET television: "We explained our positions to Mr Blatter at a meeting in Zurich on 29 May, and he assured us he understood our view."
Orfanos said the Greek FA, which receives state financial support, has undemocratic voting rules and lacks transparency.
"The HFF does not observe the laws of the country," he said.
"We want more democratic voting rules - rules that apply to all other sporting federations in Greece. If they insist, state protection will be
The HFF released their own comunique, accusing Orfanos of "playing with fire".
"He is leading Greek football to international isolation and placing it outside the international soccer community," read the statement.
"Instead of fully freeing Greek soccer from state intervention, (Orfanos) has legalized state intervention and sidelined the federation, with no concern for the consequences that have been explained to him in detail."
Under the suspension, the likes of AEK Athens, Olympiakos and Panathinaikos will not be allowed to compete in the Champions League or Uefa Cup next season.
Greek FA chief Vassilis Gagatsis, who has repeatedly clashed with Sports Minister George Orfanos over the non-independence matter, refused to comment on the suspension.
Meanwhile, the Football Association's director of communications Adrian Bevington said that he would seek clarification on the matter to find out if England's friendly against Greece at Old Trafford could go ahead.
"Obviously, if Greece have been suspended by Fifa, we would want to speak to Fifa and the Greek Federation to clarify the situation," he said.