An array of advertisers, businesses and nonprofits have criticized the plan, saying other groups might buy up domains related to their brands.
The Federal Trade Commission sent a letter to ICANN in December warning the plan could confuse consumers and enable scammers.
But ICANN is an internationally focused nonprofit that does not answer to the U.S. government.
The group said the new domain names will allow for more consumer choice and competition. The plan will also allow for more international domains in non-English languages.