As the world now knows, “Boko Haram” means “Western education is a sin,” or literally, books are evil. Using that slogan, a Ni­ger­ian extremist militia kidnapped as many as 300 schoolgirls last month and threatened to sell them as child brides last weekend, arousing international alarm and condemnation.

On Friday, in a Brentwood, Md., mosque full of Nigerian-born Muslims, the imam delivered a thundering sermon declaring for “Boko Halal,” or “books are a blessing.” In true Islam, he said, education is not a sin but a gift from God, and knowledge is for “all human beings.”

Among the gathered Muslim immigrants — men in work clothes or dashikis, women in brightly colored headdresses or scarves — there was vigorous assent. Children played on the carpeted floor, including twin girls tapping on an iPad. Their parents expressed pride in their bright futures and anger at the violent abductions that have brought horror to their homeland and shame to their faith.

“It is a terrible, terrible thing, You feel like it is your own child,” said Jamila Olaleye, 61, of Bowie, whose two grown daughters are a nurse and a social worker.

“We women should have a say. We should have our own mind,” she said angrily. “If you go to school, you can become anything. Who are they to take that away in the name of our religion?”

Until recently, the brutal actions of Boko Haram — attacks on schools, villages and officials in the rural Ni­ger­ian north — have aroused few organized expressions of concern among Ni­ger­ian Muslims in the United States. The population of mostly low-profile professionals has tended to keep religious and political feelings within family, faith and ethnic circles.

But in the past week, an explosion of outrage across Nigeria and the world over the kidnappings has changed all that. Ni­ger­ian Muslim women in headscarves are joining feminist protesters in T-shirts, and their religious leaders here are speaking out forcefully against atrocities they worry could tarnish their community’s image.

On Thursday, the leader of the National Council of Ni­ger­ian Muslim Organizations, Teslim Olarinde, flew from Florida to speak at the National Press Club and denounce Boko Haram, alongside officials from other, better-known Muslim American groups.

“Any father who hears of children being kidnapped in the name of religion knows this is wrong,” Olarinde said later in an interview. “Our religion teaches us to live in peace with others, and they are using it to justify barbaric acts.”

The same message was repeated Friday at the Brentwood prayer service, where a local council member took the microphone and stated, “We unconditionally and unambiguously condemn these backward and archaic bandits.”

Taufiq Alli, a public accountant in Prince George’s County and active member of the council, helped organize the news conference and encouraged journalists to attend the prayer service in a converted industrial building.

Alli said most members of his community are “hard-working, law-abiding people who mind their own business. But because of what is going on now, we are telling them they need to show themselves and speak out. A bad person the size of an atom can make a loud noise, and then people will think every one of us is bad.”

Nigeria is a large and complex society in which Christian and Muslim groups have often clashed, and where hostilities are often exacerbated by tribal and regional rivalries. But the recent attacks by Boko Haram have targeted both Christian and Muslim communities and provoked common feelings of anger and fear in both populations.

In the United States, the population of about 260,000 Ni­ger­ian immigrants includes both Christians and Muslims. Most are clustered around cities in Texas, New York and California as well as the greater Washington region. They are known as an accomplished and well-educated group, including doctors and scientists. They maintain separate places of worship but generally cordial relations.

The Muslims among them have rarely been targets of American hostility as some Muslim immigrants were after the attacks of Sep. 11, 2001, and other incidents. But the sudden notoriety of Boko Haram has made them feel the need to make clear that they are both mainstream and pro-American.

“I’m proud to be an American and grateful to be here,” said Taibat Memudu, 46, a health insurance manager from Hyattsville who attended the Brentwood service. “People are associating these events with Muslims, but those are not Muslims. They are just hiding behind our religion and trying to blacken it.”