Demonstrators gathered in front of the Nigerian Embassy in Washington on Tuesday. (Jahi Chikwendiu/The Washington Post)

The kidnapping of hundreds of Nigerian schoolgirls last month has sparked an international outcry, something that only intensified this week when the leader of the Nigerian Islamist group responsible for the kidnapping described them as “slaves” and threatened to sell them.

It took time for the story of the kidnapping to spread around the world, but once it did, the building anger was channeled through social media campaigns on Facebook and Twitter. In the United States, this outcry has taken the form of protests stretching from coast to coast, rallies that are similar to events happening in Nigeria and elsewhere around the world.

Hundreds of protesters gathered in New York’s Union Square over the weekend, bringing signs and bullhorns to decry the inaction of Nigeria’s government:

“I am angry!” shouted Makho Ndlovu, 32, of Brooklyn. “It makes no sense that girls can be abducted and the world doesn’t care. I am angry! To the Nigerian government, our eyes are watching. To Barack Obama, our eyes are watching. To the United Nations, our eyes are watching.”

In Washington, dozens of people converged on the Nigerian Embassy. They came together Tuesday morning because, as one of them said, “I’m a mother and I would feel the same way if my daughter were in danger.”

Protesters spoke out at the Nigerian embassy in Washington, D.C. to express their disappointment in the Nigerian government after an extremist group kidnapped nearly 300 girls on April 15th. (Jackie Kucinich/The Washington Post)

Demonstrators rallied in Los Angeles on Monday against the kidnapping, as similar rallies popped up in HoustonBaltimore, Syracuse and other cities. Other events are also planned in the coming days for cities and college campuses across the United States, as well as locations around the world.

Meanwhile, if you’re looking for more information about the kidnapping, Ishaan Tharoor has a good primer over at WorldViews that includes more about what happened and some background on Boko Haram, the Nigerian Islamist group that has claimed responsibility.