WASHINGTON, June 22 (Xinhua) -- The White House confirmed Tuesday that the country will not hit U.S. President Joe Biden's goal of getting 70 percent of American adults to receive at least one COVID-19 vaccine shot by the Fourth of July.

US first lady Jill Biden (L) comforts Adriana Lyttle, 12, as she receives her vaccine at a Covid-19 vaccination site at Ole Smoky Distillery in Nashville, Tennessee, June 22, 2021.

"We want every American in every community to be protected and free from fear of the virus. That's why we'll keep working to vaccinate more Americans across the summer and into the fall ... we are not stopping at 70 percent and we're not stopping on July Fourth," Zients said at a White House COVID response briefing.

He said U.S. officials are working with state and local leaders to reach younger people.

"We think it'll take a few extra weeks to get to 70 percent of all adults with at least one shot with the 18- to 26-year-olds factored in," he said.

Zients said many younger Americans have been less eager to get a shot, urging vaccinations of the younger population to prevent the spread of the highly contagious Delta variant.

Biden announced in early May the goal to administer at least one dose of a COVID-19 vaccine to 70 percent of American adults by July 4.