Updated at 8:20 p.m.

The D.C. chapter of the NAACP has begun investigating the termination of three social studies teachers at Howard University Middle School of Mathematics and Science, after parents alleged they were targeted for teaching extra lessons about African and African American history.

However, Akosua Ali, president of the NAACP D.C. chapter, said the preliminary finding is that the three were not discharged for teaching black history.

Nevertheless, she said, the civil rights group is concerned about how the teachers were treated, and about other issues connected to the overall quality of the education received by the middle school’s students.

The announcement of the NAACP investigation came hours after students at the charter school staged a protest and gave school administrators a list of demands, including their priority: “New Social Studies teachers that will be treated with respect.”

School officials did not respond to requests for comment, and the teachers could not be reached on Monday.

Adilah Bilal, president of Parents in Action, a parent group at the school, said the social studies teachers came to the group on Jan. 22 and said they were planning to resign. Bilal said the reason the teachers gave was that they wanted to introduce more African history into a curriculum that focuses heavily on Greek and Roman history, but they claimed the administration did not support them. One teacher said that she had been written up for a lesson she gave about former mayor Marion Barry near the time of his death, Bilal said.

She said the teachers had planned to resign this Friday, so they could stay long enough to help students meet the Feb. 2 deadline to apply to high school through the citywide enrollment lottery. In the meantime, the parents resolved to hire a mediator to help the teachers and administrators work out the dispute. But early last week, administrators asked the teachers to leave immediately, she said.

The charter middle school is on the campus of Howard University, a historically black school. The middle school’s students gathered in the university’s main quad at about 11 a.m. Monday and formed a circle. Some students held up a poster that stated, “They don’t care about us.” Others held up pan-African flags.

News of the demonstration spread on Twitter using the hash tag #MS2Protest, and many people online encouraged the students to stand up for their rights.

Angelicque Blackmon, the middle school’s chief academic officer, is new this year.

School parents said they confronted her twice last week, asking how and why the teachers left so abruptly. “We just want to know what’s going on,” said Dorothy Lowery, whose daughter is in the sixth grade. In particular, she said she wants to know what is in the social studies curriculum.

“These are African American kids. They should learn African American history,” she said.

Lowery said the teachers had been forced to leave the school in the middle of the day and were given termination papers in front of the students. “My daughter came home very upset,” she said.

In a statement, the D.C. Public Charter School Board said public charter schools “are allowed the sole discretion on specific academic decisions including the hiring and termination of their staff and teachers.”

The board said it uses a “variety of methods — including reports, analysis and site visits — to ensure that public charter schools are providing quality educational opportunities to their students and are complying with the law.”