U.S. officials on Tuesday said they had thwarted a plot to carry out a terror attack in the U.S. on Election Day by an Afghan citizen with ties to ISIS. The Justice Department unsealed charges against Nasir Ahmad Tawhedi, 27, who now lives in Oklahoma City, Oklahoma and was arrested Monday. DOJ accuses Tawhedi of purchasing two AK-47 assault rifles, ten magazines, and 500 rounds of ammunition from an FBI source. It says his brother-in-law, a juvenile, acted as an accomplice. Court filings indicate Tawhedi said he had planned to carry out an attack on Election Day in both seized communications with an ISIS recruiter and in speaking to law enforcement after his arrest. They say he intended to target large gatherings of people and that both he and his brother-in-law expected to die as martyrs in the attack. “This defendant, motivated by ISIS, allegedly conspired to commit a violent attack, on Election Day, here on our homeland," FBI Director Christopher Wray said in a statement.  "I am proud of the men and women of the FBI who uncovered and stopped the plot before anyone was harmed. Terrorism is still the FBI's number one priority, and we will use every resource to protect the American people." Tawhedi was charged with conspiring and attempting to provide material support to ISIS, which carries a maximum sentence of 20 years in prison, and receiving a firearm to carry out a crime of terrorism, which carries a maximum prison sentence of 15 years. According to court documents unsealed Tuesday, Tawhedi came to the U.S. shortly after the U.S. withdrawal from Afghanistan on a Special Immigrant Visa given to those who aided the military during the U.S.’s 20 year war in Afghanistan. In addition to purchasing the weapons, Tawhedi was also in the process of selling his home and had purchased one-way tickets for his wife and other family members for Oct. 17 so that they could return to Afghanistan and live according to “pure Islam.” The court filings show Tawhedi speaking with an ISIS recruiter and discussing plans to purchase the weapons and have his family settled when they arrived in Afghanistan. While it does not offer many details about Tawhedi’s planned attack, it notes that over the summer he searched how to access cameras in Washington, D.C., visiting the webcams for both the White House and the Washington Monument. He also researched gun laws, including which states have concealed carry. “As charged, the Justice Department foiled the defendant’s plot to acquire semi-automatic weapons and commit a violent attack in the name of ISIS on U.S. soil on Election Day,” Attorney General Merrick Garland said in a statement.  “We will continue to combat the ongoing threat that ISIS and its supporters pose to America’s national security, and we will identify, investigate, and prosecute the individuals who seek to terrorize the American people.” Story updated at 6:56 p.m. EDT