MSNBC has fired the employee who sent out a controversial Tweet involving a Cheerios commercial that features a biracial family.

In a statement to The Hollywood Reporter, MSNBC president Phil Griffin called the Tweet "outrageous and unacceptable."

STORY: Republicans Boycott MSNBC Over Cheerios Tweet

"We immediately acknowledged that it was offensive and wrong, apologized, and deleted it," the statement continued. "We have dismissed the person responsible for the tweet. I personally apologize to Mr. Priebus and to everyone offended. At MSNBC we believe in passionate, strong debate about the issues and we invite voices from all sides to participate. That will never change."

MSNBC anchor Ari Melber read Griffin's statement at the end of the network's 3 p.m. hour.

The tweet prompted Republican National Committee chairman Reince Priebus to call for a Republican boycott of the network.

The full tweet, sent at 8:06 p.m. from the MSNBC Twitter account, read: "Maybe the rightwing will hate it, but everyone else will go awww: the adorable new #Cheerios ad w/biracial family."

The Cheerios ad is the second spot to feature a biracial couple and their daughter, "Gracie." When General Mills premiered the first spot last May, social media erupted with vitriolic, racist comments. The company disabled the comments section on the ad's YouTube site, though the spot also received much praise.

Priebus sent a letter Thursday morning to Griffin denouncing what he characterized as "demeaning attacks" that "have become a pattern" at MSNBC.

"With increasing frequency many of your hosts have personally denigrated and demeaned Americans -- especially conservative and Republican Americans -- without even attempting to further meaningful political dialogue," wrote the RNC chairman.

It is the latest embarrassing gaffe for MSNBC, which has already parted ways with Martin Bashir and Alec Baldwin, while weekend host Melissa Harris-Perry issued a tearful apology for belittling Mitt Romney's adopted African-American grandson.

In an e-mail to "interested parties," RNC communications director Sean Spicer, noted that Priebus and Griffin spoke by phone on Thursday. "We appreciate Mr. Griffin’s admission that their comment was demeaning and disgusting, and the Chairman accepted his apology," wrote Spicer, adding that the RNC "will aggressively monitor the network to see whether their pattern of unacceptable behavior actually changes."

He continued: "We don’t expect their liberal bias to change, but we will call them out when political commentary devolves into personal and belittling attacks."

In an interview earlier this month with The Hollywood Reporter, Griffin acknowledged past mistakes, but vowed to move forward. "These were judgment calls made by some of our people," he said. "We quickly took responsibility for them and took action. They were unfortunate, but I'm not going to allow these specific moments of lack of judgment to define us."