UPDATED: Ann Coulter vs Delta tweet battle continues

Conservative pundit Ann Coulter unleashed a tweetstorm on Delta Air Lines on Saturday night, complaining about being moved out of a particular seat with extra legroom that she pre-booked.

In one tweet Coulter refers to Delta as "the worst airline in America."

Coulter had booked a preferred seat in the exit row with extra legroom and was moved to a different seat in the same exit row, according to Delta. The airline said it "inadvertently" moved Coulter from an aisle seat to a window seat in the exit row on the other side of the aisle "when working to accommodate several passengers with seating requests."

Although Atlanta-based Delta has a mostly non-union workforce with pilots as the only major unionized employee group, Coulter asked: "Does your union hate you, @Delta?"

Delta responded via Twitter with an apology.

The airline said it is sorry she "did not receive the seat she reserved and paid for," and will refund the $30 extra Coulter paid for the preferred seat.

Coulter also posted a photo of the passenger she said was given her seat.

>>READ: Are you allowed to take photos and video of airline employees and other passengers on a plane? The answer may surprise you.

In describing the series of tweets from Coulter, Delta said "what started out as complaints eventually turned into a public attack on the airline’s employees and customers."

Here's more from Coulter's tweetstorm.

On JetBlue vs Delta:

Coulter on Delta airport customer service and in-flight crew:

Coulter on a fellow passenger:

In addition to the apology to Coulter, Delta issued a statement Sunday saying "we are disappointed that the customer has chosen to publicly attack our employees and other customers by posting derogatory and slanderous comments and photos in social media. Her actions are unnecessary and unacceptable."

"Delta expects mutual civility throughout the entire travel experience," Delta said in its statement.

On Sunday, Coulter tweeted further on the Delta incident.

On Twitter, Delta responded:

And on Sunday evening and Monday, Coulter responded in kind:

-- Stay up to date on the latest news on Atlanta airline travel by following  Atlanta Airport News Now on Facebook --

MORE:

Are you allowed to take photos and video of crew and other passengers on a plane? The answer may surprise you.

Delta bets some will pay extra for comfort

Airline passenger posts video of family booted off flight, Delta apologizes

Delta: 'Up-sell' fare strategy working well

Flier, family booted over seat dispute

Delta can now offer up to $9,950 to passengers willing to give up seats

Talk of the Town blog: Delta and other air carriers score big profits on passenger misery

Delta aims to bring in more cash from extras

Delta selling Comfort+ fares for extra-legroom seats

Delta flight attendants to remain non-union

Delta customer service workers reject union