This week, an American Islamist who has been fighting with an al-Qaeda-linked group in Syria perpetrated a suicide strike, the first to be carried out by a U.S. citizen in Syria. He was part of a contingent of Western Jihadis fighting in the country, who officials fear could bring the war back home. 

Authorities confirmed yesterday that the man grew up and went to school in Florida, but did not reveal his name. In Syria, he went by Abu Hurayra Al-Amriki, and was praised for the killing on social media sites, according to CNN, which also notes that "Al-Amriki" means American in Arabic. 

According to the New York Times, more than 70 Americans are currently fighting against Syrian President Bashar al-Assad, and more than 3,000 Westerners are fighting in the civil war altogether. To prevent the jihadis from carrying out attacks on Western soil, European and American officials are making it more difficult for them to return. The U.K. has revoked the citizenship of 20 jihadis, and has made 40 "Syria-related arrests" over three months this year. Last week, British citizen Mashudur Choudhury was convicted for his actions in Syria, the first to be officially punished for fighting alongside Syrian Islamists. "There's going to be a diaspora out of Syria," said FBI Director James Comey, "And we are determined not to let lines be drawn from Syria today to a future 9/11."

Some Western fighters do warn of future unrest at home. The New York Times reached a North American Islamist, who goes by Abu Muhajir, via text message. He told the publication that “We can only expect a response," as attacks take place on the ground in Syria and neighboring countries. "I knew this war will be long,” adding that it “Requires steadfastness.” But others plan on dying in Syria. Abu Sumayyah told the Times via Twitter that he's "looking at the hereafter because the reward is a lot.”

The return of Western militants to their home countries is another method for groups like al-Qaeda to spread their message abroad. Back in March, the English-language magazine Inspire offered instructions on how to construct car bombs, and urged militants in the U.S. to target urban areas like Los Angeles, Chicago, and New York City. These threats, plus the increased use of social media by al-Qaeda and other terrorist groups, complicate the West's counterterrorism efforts.