NEW YORK (AP) -- Some Taco Bell fans are angry after they couldn't get their hands on the chain's new tacos made with Cool Ranch Doritos shells a day early.

The fast-food chain had announced on Facebook this week that fans would be able to buy its highly-anticipated Cool Ranch Doritos Locos Tacos on Wednesday, a day earlier than planned. But then some fans began posting on the Facebook page complaining that their local restaurants didn't have them yet. They said they were told by local employees that the tacos wouldn't be available until Thursday.

"VERY disappointed!" one fan wrote. "Boo to you," wrote another. One fan posted a letter to the chain online, detailing how he and a friend made a trip to their local Taco Bell after midnight Wednesday to get their first taste of the new tacos. He said they ended up getting the regular Doritos Locos Tacos because they were "basically committed anyway."

Taco Bell, which is owned by Yum Brands Inc. of Louisville, Ky., apologized in a statement and said it was humbled by the overwhelming response. The chain said it wanted to assure fans that Cool Ranch Doritos Locos Tacos will be available nationwide Thursday. It also said it was working to have all participating restaurants honor the early release for the remainder of Wednesday.

Meanwhile, other posts on Taco Bell's Facebook page mocked those who were complaining. "Oh my god all of you shut up, it's just a taco," one person wrote.

Taco Bell introduced its Doritos Locos Tacos in Nacho Cheese flavor a year ago. CEO Greg Creed has said the tacos have been a runaway hit, accounting for about a quarter of all taco sales. The chain plans to keep rolling out new flavors, including a spicy "Flamas" flavor later this year.

A Doritos Locos Taco costs $1.39, while a regular taco costs 99 cents.