INDIANAPOLIS (AP) _ Activists slugging it out over a proposed constitutional amendment banning gay marriage are turning their focus to the Indiana Senate as the legislative battle enters its second round of the 2014 session.

Leaders with the umbrella group opposing House Joint Resolution 3 asked their supporters to begin dialing up senators to express their opposition. Meanwhile, supporters of HJR 3 sent out blast notices urging members of the Senate to restore a ban on civil unions that was removed in the House earlier this week.

House lawmakers approved an altered version of the ban Tuesday afternoon, one day after rejecting a ban on civil unions included in the measure. But if Senators approve the amended House bill, it will likely delay a referendum on the amendment until 2016.