Former President Barack Obama will host hundreds of guests at his 60th birthday party this coming weekend on Martha's Vineyard in Massachusetts amid concerns about spreading the delta variant of COVID-19, according to a source familiar with the plans.

       A COVID coordinator will ensure all Centers for Disease Control and Prevention, state and local guidelines are followed at the party, the source said about the affair, which will be held outdoors.

       Jeff Neira/ABC via Getty Images, FILE

       In this June 3, 2021, file photo, former President Barack Obama sits down for a one-on-one interview with Good Morning America Co-Anchor Michael Strahan.

       Guests will be required to submit proof of a negative COVID-19 test to the coordinator before attending the party, the source said.

       Martha's Vineyard, an island in Dukes County, Massachusetts, is currently considered at a "moderate" level of transmission risk, according to CDC data.

       Axios first reported on details of the party.

       Jonathan Ernst/Reuters, FILE

       In this Aug. 7, 2016, file photo, President Barack Obama smiles after putting on the first green at Farm Neck Golf Club during his annual summer vacation on Martha's Vineyard, in Oak Bluffs, Mass.

       Despite the planned effort to ensure a safe event, the party comes after a major breakout of COVID-19 cases abut 100 miles away in Provincetown, Massachusetts, which left more than 800 people infected, resulting in at least 7 hospitalizations.

       Officials said 74% of those in the infected Provincetown cluster were vaccinated.

       MORE: CDC mask decision followed stunning findings from Cape Cod beach outbreak

       Kevin Lamarque/Reuters

       President Joe Biden waves from his bike while riding at Cape Henlopen State Park in Rehoboth Beach, Del., June 3, 2021.

       President Joe Biden is not planning to attend the gathering, according to a White House official.

       "While President Biden is unable to attend this weekend, he looks forward to catching up with former President Obama soon and properly welcoming him into the over 60 club," the administration official said. Biden is scheduled to spend the weekend at his home in Rehoboth Beach, Delaware.

       "I would note first that former President Obama has been a huge advocate of individuals getting vaccinated," White House press secretary Jen Psaki said Monday.

       She noted the CDC's current guidance on masking pertains only to indoor settings in high or substantial transmission risk zones.

       "In addition, there is testing requirements and other steps they're taking," Psaki added.

       MORE: US passes major vaccine milestone: 70% of adults now have at least 1 shot, White House says

       The Obamas have identified various charities for guests to consider supporting, rather than giving birthday gifts, including My Brother’s Keeper Alliance, the Girls Opportunity Alliance, and the Obama Foundation’s Global Leadership programs.