The nation's two biggest fantasy sports sites, DraftKings and FanDuel, plan to suspend all college sports gaming in a deal with the NCAA, ESPN reported Thursday, just days before the college men's basketball final.

For months, the sites have encountered pushback from smaller rivals and officials in several states considering whether to legalize the multi-million-dollar gaming. College sports represents only 3 percent of FanDuel's revenue, with NFL games making up a much more lucrative market, ESPN reports.

Gaming officials tell the network their decision was voluntary, and takes effect at the end of the week.

FanDuel "has had months of productive conversations with the NCAA, their member institutions and various state legislators to better understand their concerns around fantasy sports contests based on amateur athletics," a company spokesperson told ESPN.

DraftKings added it will "work closely with the NCAA and lawmakers on a carve-out for collegiate sports in any proposed regulatory framework moving forward."

NCAA president Mark Emmert responded, "This action culminates months of hard work between all parties to reach a place that is good for amateur sports and most importantly, the young people who participate."