Correction: An earlier version of this story incorrectly described the Yazidi community of northern Iraq as a Chrsitian sect. This version has been corrected.

A group of Egyptian Coptic Christians, including Amer Sabet, holding a cross, march from the White House toward the U.S. Capitol in remembrance of 21 Egyptian Coptic Christians recently beheaded in Libya by Islamic State. (Jahi Chikwendiu/The Washington Post)

Hanna Asaad, a network engineer in Fairfax, Va., grew up in the village of Aloor in southern Egypt. He was able to immigrate to the United States several years ago, but his best friend and cousin, Samuel Alham, sought work as a laborer in nearby Libya, like many other Coptic Christians in the impoverished region.

Shortly after Christmas, Alham and 20 of his fellow Coptic laborers were kidnapped by Islamic State militants in Libya. In mid-February, they were marched to a Mediterranean beach in handcuffs and orange prison jumpsuits. Then they were beheaded with knives as a video camera recorded the gruesome scene.

On Tuesday, Asaad, 29, joined 20 protesters who donned orange jumpsuits and stood outside the White House, then knelt with their hands behind their backs. Behind them, other demonstrators held up photographs of the real victims and the blood-red waves where their headless corpses were thrown.

“I kept calling my cousin and telling him he had to leave Libya, but there was no safe way out,” Asaad said. “The militants came looking for Christians and then took them away. They murdered my cousin, my nephew and my classmates. Someday soon they will start murdering people in this country.”

About 50 demonstrators, who marched slowly from the White House to Capitol Hill under police escort, demanded that U.S officials take more aggressive action against the Islamic State and other radical Islamist groups, including Boko Haram in Nigeria and the Muslim Brotherhood in Egypt.

Hanna Asaad, front, is among of group of Egyptian Coptic Christians marching toward the White House on Tuesday in remembrance of 21 Egyptian Coptic Christians recently beheaded in Libya by Islamic State. (Jahi Chikwendiu/The Washington Post)

“Obama, Obama, did you see? Christian blood in the sea,” they chanted.

For Copts in the Washington area and across the United States — mostly a population of educated, professional émigrés — the seaside slaughter was an especially horrific incident in a history of increasing persecution that the Christian minority group has faced in its native Egypt. Recent attacks included the bombing of a church on New Year’s Day, 2011, in the city of Alexandria, which left 21 worshippers dead and 79 injured.

Meanwhile, as militant Islamist ideology spreads, Christian groups are confronting attacks in other parts of the Middle East and South Asia.

On Tuesday, human rights groups in Syria reported that at least 90 Assyrian Christians had been kidnapped by Islamic State militants after they seized two Christian villages from Kurdish forces in northern Syria. One demonstrator outside the White House was a Syrian who said some of his relatives were among those taken and missing.

In northern Iraq, the Islamic State has harassed communities of Yazidis, followers of a religion influenced by Christianity and other ancient belief systems whom the terrorist group accuses of devil worship. In August, more than 40,000 Yazidis were driven from their villages and took refuge on a mountainside, prompting a massive U.N. humanitarian rescue effort backed by the United States.

“ISIS wants to drive all Christians from the Middle East. Obama has to act before the whole region turns to fire,” Atef Jacob, 70, an engineer and a Coptic immigrant living in Centreville, Va., said at the protest. ISIS is another name for the extremist group.

The Obama administration has faced an increasingly chaotic situation in the Middle East since the Arab spring of 2011, including the rise of the Islamic State, the deepening Sunni-Shiite conflict in Iraq, the collapse of the Muslim Brotherhood government in Egypt, the intransigence of Syria’s dictatorship and the deadly attack on a U.S. consulate in Libya. At home, it has faced conflicting pressure to act more boldly and refrain from entering a new war.

A group of Egyptian Coptic Christians pause in front of the Newseum during a march from the White House toward the U.S. Capitol in remembrance of 21 Egyptian Coptic Christians recently beheaded in Libya by Islamic State. (Jahi Chikwendiu/The Washington Post)

In the Washington region, Copts have emerged as a small but vocal source of pressure on the administration, in part because of their Christian heritage and in part because many are affluent, well-organized U.S. citizens. Most originally came from Cairo or other Egyptian cities and have remained deeply engaged in Egyptian politics.

Asaad is one of the few émigrés here who grew up in the same struggling rural area as the slain laborers — anonymous men who toiled abroad to feed their families back home. In an interview, he described how his cousin and other friends were living eight to a room near Libyan construction sites when ISIS militants started raiding their hostels and singling out Christians to take as hostages.

“They believe that anyone who is not a Muslim, who is not a believer, must be killed,” he said. “They went looking for Christians and they identified them by their crosses.” He pulled up his sleeve and showed a small tattooed cross on his wrist, a traditional Coptic ritual performed on newborns.

“This is our identity,” he said. “This is how they killed my cousin.”