McCALLA, AL-Students from an Alabama high school held up an offensive banner which read "Hey, Indians, get ready to leave in a Trail of Tears Round 2". A second banner was held up at a school in Tennessee which stated "Trail of Tears".

Tod Humphries, the principal at McAdory High School in McCalla, Alabama, said he takes "full responsibility" for the banner.

The banner was directed at the school's opponents, the Pinson Valley High Indians. On the school's website, the principal apologized noting that Native Americans suffered "horrific atrocities" on the Trail of Tears.

"Please accept our sincere apologies to the Native American people," Humphries wrote, " and to anyone who was offended by the reference to an event that is a stain on our nation's past forever."

He went on to claim that he did not approve of the banner before it was used at the game and said that "the person who would normally be responsible for approving such signs is out on maternity leave."

The banner presented by high school students in Dyersburg, Tennessee, was also posted on a Facebook page managed by the coaching staff at Dyersburg High School. But after complaints were made to the principal, they were removed.

A graduate student at Harvard University, Adrienne Keene, told NBC News that she considered the banner nauseating.

"I definitely felt sick to my stomach to see something I consider such an atrocity in the past of my own family," Keene said.

Keene is a member of the Cherokee Nation of Oklahoma and her ancestors were systematically removed from their homelands by the U.S. government during what came to be known as the Trail of Tears between 1838 and 1839.

Thousands of Native Americans from numerous tribes died from exposure and exhaustion as they were marched for more than 230 miles after U.S. President Andrew Jackson passed the Indian Removal Act of 1830. The act forced assimilation among Native Americans to open up millions of acres of land to mostly white settlers.

Keene said she believes the banner is indicative of a failing school system and of how U.S. citizens view Native Americans.

"This is representative of the miseducation in our school systems, especially with regard to Native peoples," she said. "This points to a lot of underlying issues about how Native Americans are perceived in American society."

Chase Iron Eyes, a Standing Rock and Oglala Lakota and co-founder of Last Real Indians, a website devoted to providing a platform for Native American writers, told NBC News that the banner prompted "expected shock" throughout Indian country.

"When institutions and sports organizations have Indians as mascots or monikers the unavoidable result is racially or socio-politically driven offensive material," he wrote in an email.

Humphries ended his apology with a commitment to teaching his students about the Trail of Tears. "In response to the 'bust thru' sign used by McAdory High School during the Round 2 State Play-Off game versus Pinson Valley High School, all social studies and history teachers will re-teach and/or review units concerning Native American displacement following the Indian Removal Act of 1830," he wrote.