ATLANTIC CITY, N.J. -- Sports betting company DraftKings apologized Monday after using the Sept. 11, 2001, terror attacks to entice people to bet on baseball and football games on the anniversary of the tragedy that killed nearly 3,000 people.

The Boston-based company offered users a 9/11-themed promotion that required three New York-based teams -- the Yankees, Mets and Jets -- to win their games Monday, the 22nd anniversary of the attacks on the World Trade Center and Pentagon and the downing of a passenger jet in a field in Pennsylvania.

After an outcry on social media from people offended by the promotion, titled "Never Forget," DraftKings took it down and apologized.

"We sincerely apologize for the featured parlay that was shared briefly in commemoration of 9/11," the company wrote. "We respect the significance of this day for our country and especially for the families of those who were directly affected."

Brett Eagleson, whose father, Bruce, was killed in the World Trade Center, runs a families and first responders organization called 9/11 Justice. He decried the DraftKings offer as "tone deaf."

"It is shameful to use the national tragedy of 9/11 to promote a business," he told The Associated Press. "We need accountability, justice and closure, not self-interest and shameless promotion."

DraftKings would not say how many people placed bets as a result of the offer, nor whether those bets remain valid or have been canceled.

The Yankees visit the Red Sox on Monday night, and the Mets host the Diamondbacks. The Jets open their season at home against the Bills.

Bets of the type DraftKings offered, in which multiple games or outcomes are bundled into a single wager, are extremely profitable for sportsbooks, and offering gamblers preselected groupings, called parlays, is an important part of sports wagering.

Information from The Associated Press was used in this report.