Just days after Rhode Island Governor Lincoln Chafee signed a civil unions bill into law, backers of full marriage for gay and lesbian couples have vowed to return next year.

Chafee on Saturday signed the civil unions bill into law, making Rhode Island the fifth after Illinois, New Jersey, Delaware and Hawaii to recognize gay couples with civil unions.

The governor, who supports giving gay couples the right to marry, expressed reservations about the law's limited benefits but added that it would protect thousands of families, saying that the legislation “brings tangible rights and benefits to thousands of Rhode Islanders” and that it “provides a foundation from which we will continue to fight for full marriage equality.”

Lawmakers shifted from supporting a gay marriage law to civil unions after it became clear a marriage bill would not clear the Republican-controlled Senate.

Gay rights groups say they object to an amendment sponsored by Rep. Arthur J. Corvese that exempts religious organizations from the requirement that they treat gay couples in a civil union as they would any other married couple, and add that civil unions are not equal to marriage.

Ray Sullivan, campaign director for the group Marriage Equality Rhode Island, told the Associated Press on Tuesday that the fight will continue next year, and that his group plans to make marriage equality a key issue in the 2012 elections.