(CNN) -- Same-sex couples in Chicago and surrounding Cook County can marry immediately and won't have to wait until June 1 for a state law legalizing gay marriage to take effect, a federal judge ruled Friday.
"There is no reason to delay further when no opposition has been presented to this Court and committed gay and lesbian couples have already suffered from the denial of their fundamental right to marry," U.S. District Court Judge Sharon Johnson Coleman wrote in a lawsuit.
"Although this Court finds that the marriage ban for same-sex couples violates the Fourteenth Amendment's Equal Protection Clause on its face, this finding can only apply to Cook County based upon the posture of the lawsuit," the judge wrote.
Cook County Clerk David Orr said his downtown Chicago office would be open until 7 p.m. Friday issuing marriage licenses to same-sex couples.
"I'm thrilled same-sex couples who want to get married won't have to wait any longer" Orr said in a statement. "We are very excited to celebrate this historic milestone with every loving couple from today onward."
In November, the Illinois General Assembly passed the Religious Freedom and Marriage Fairness Act, making Illinois the 16th state in the nation to legalize same-sex marriage. The measure goes into effect June 1
Last month, the gay rights group Lambda Legal and the ACLU filed a class-action lawsuit in Illinois on behalf of same-sex couples who wanted to immediately obtain marriage licenses in Cook County.
Christopher Clark, counsel for Lambda Legal, said the case originally arose after a couple facing life-threatening illness came forward saying they didn't feel they could wait until June to be married.
Clark called Friday's ruling an "absolute ringing affirmation of the principles of liberty and equality that are at the foundations of our constitution."
Clark said the ruling sets a precedent for same-sex marriage in other states and called it "another step in resolving the issue across the country."