Seattle's Clint Dempsey has been suspended from the U.S. Open Cup for the next two years or a maximum of six matches -- whichever is greater -- for his actions during a June 16 match.

Dempsey, who also apologized for confronting referees later on Thursday, will be ruled out of playing in all of his club's cup games in 2016 and 2017 at the least. He was also fined an undisclosed amount.

Should the Sounders lose early in those tournaments and fail to play the required six matches in that time, Dempsey's ban will be extended until they do, meaning the U.S. national team captain could not play another cup game until 2022 should the Sounders drop all of their opening matches over the next six years.

MLS teams can play up to five games each year if they reach the final, assuming the tournament format stays the same.

The Open Cup ban doubles the punishment doled out less than a week ago by MLS, which sidelined Dempsey for three games despite rules that appeared to call for a minimum suspension twice that long.

Clint Dempsey's antics towards officials will prevent him from playing in the U.S. Open Cup for all of 2016. Jennifer Buchanan/USA TODAY Sports

Dempsey was red carded during the Sounders' fourth-round match against the Portland Timbers after tearing up referee Daniel Radford's notebook. He then had to be restrained from confronting Radford and clapped in an assistant referee's face on his way off the field.

The league's decision prompted a sharp rebuke from its referees, who called the reprimand a "slap on the wrist."

But if MLS disciplinarians cut the U.S. national team captain any slack the U.S. Open Cup's sure didn't. The cup's five-person Adjudication and Disciplinary Panel -- which is kept anonymous -- unanimously voted for the stiffer punishment.

Dempsey apologized for the first time in a tweet later on Thursday evening.

I would like to apologize for my actions in the U.S. Open Cup. - Clint Dempsey (@clint_dempsey) June 25, 2015

Dempsey's suspension matches the one former Chicago Fire forward Cuauhtemoc Blanco received following an altercation with a D.C. United staffer in 2008.