Illinois's attorney general says county clerks statewide can immediately begin issuing marriage licences to same-sex couples even though the state law legalizing gay marriage doesn't take effect until June.

Democratic Attorney General Lisa Madigan issued the guidance Tuesday in response to a question from Macon County Clerk Stephen Bean.

A state law legalizing same-sex marriage takes effect June 1, but a federal judge in Chicago ruled last month that Illinois's original ban on gay marriage was unconstitutional.

The court said the ruling only applied to Cook County — Illinois's most populous county, which includes the city of Chicago. But in a letter to Bean, Madigan said that because current restrictions on gay marriage are unconstitutional, same-sex couples asking for a marriage licence in any county can be given one.

Democratic Gov. Pat Quinn says county clerks should quickly follow Madigan's guidance.