Starbucks is ending its "Race Together" campaign, in which baristas were encouraged to write on the iconic white cups to "broaden the dialogue" about race, the company's CEO wrote in a letter Sunday.

The campaign, which started a week ago and incorporated writing or stickers, drew significant criticism on social media.

"This phase of the effort -- writing 'Race Together' (or placing stickers) on cups, which was always just the catalyst for a much broader and longer term conversation -- will be completed as originally planned today, March 22," CEO Howard Schultz wrote on the coffee company's website. "But this initiative is far from over."

Schultz said he never expected "universal praise" for the idea. He said there were more activities planned in the near future, including special sections coproduced with USA Today.

"An issue as tough as racial and ethnic inequality requires risk-taking and tough-minded action," Schultz wrote. "And let me reassure you that our conviction and commitment to the notion of equality and opportunity for all has never been stronger."