WASHINGTON, D.C. — The FBI has arrested an Afghan man who officials say was inspired by the Islamic State militant organization and was plotting an Election Day attack targeting large crowds in the US, the Justice Department said Tuesday.

Nasir Ahmad Tawhedi, 27, of Oklahoma City told investigators after his arrest Monday that he had planned his attack to coincide with Election Day next month and that he and a co-conspirator expected to die as martyrs, according to charging documents.

Tawhedi, who arrived in the US in September 2021, had taken steps in recent weeks to advance his attack plans, including by ordering AK-47 rifles, liquidating his family's assets and buying one-way tickets for his wife and child to travel home to Afghanistan, officials said.

The arrest comes as the FBI confronts heightened concerns over the possibility of extremist violence on U.S. soil, with Director Christopher Wray telling The Associated Press in August that he was "hard pressed to think of a time in my career where so many different kinds of threats are all elevated at once."

"Terrorism is still the FBI's number one priority, and we will use every resource to protect the American people," Wray said in a statement Tuesday.

An FBI affidavit does not reveal precisely how Tawhedi came onto investigators' radar, but cites what it says is evidence from recent months showing his determination in planning an attack. A photograph from July included in the affidavit depicts a man investigators identified as Tawhedi reading to two young children, including his daughter, "a text that describes the rewards a martyr receives in the afterlife."

Officials say Tawhedi also consumed Islamic State propaganda, contributed to a charity that functions as a front for the militant group and communicated with a person who the FBI determined from a prior investigation was involved in recruitment and indoctrination of people interested in extremism. He also viewed webcams for the White House and the Washington Monument in July.

The criminal complaint, filed by the Justice Department, against Nasir Ahmad Tawhedi, 27,of Oklahoma City is photographed Tuesday, Oct. 8, after the FBI arrested the man who officials say was inspired by the Islamic State militant organization and was plotting an Election Day attack targeting large crowds in the US. AP PHOTO

Tawhedi's alleged co-conspirator was not identified by the Justice Department, which described him only as a juvenile, a fellow Afghan national and the brother of Tawhedi's wife.

After the two advertised the sale of personal property on Facebook, the FBI enlisted an informant last month to respond to the offer and strike up a relationship. The informant later invited them to a gun range, where they ordered weapons from an undercover FBI official who was posing as a business partner of the informant, according to court papers.

Tawhedi was arrested Monday after taking possession of two AK-47 rifles and ammunition he had ordered, officials said. The unidentified co-conspirator was also arrested but the Justice Department did not provide details because he is a juvenile.

After he was arrested, the Justice Department said, Tawhedi told investigators he had planned an attack for Election Day that would target large gatherings of people.

Tawhedi was charged with conspiring and attempting to provide material support to the Islamic State, which is designated by the US as a foreign terrorist organization. The charge is punishable by up to 20 years in prison.

He appeared in court Tuesday and was ordered detained. An email to an attorney listed as representing him did not immediately return an email seeking comment.

It was not immediately clear if he had a lawyer who could speak on his behalf.

A for-sale sign stood in the yard outside a modest, two-story brick home listed as being connected to Tawhedi's family in the Oklahoma City suburb of Moore.

A woman who identified herself as Tawhedi's wife declined to discuss the case.

"We don't want to talk in the media," said the woman, who did not give her name.

Tawhedi entered the US on a special immigrant visa in 2021 and has been on parole status pending the conclusion of his immigration proceedings, the Justice Department said. The program that permits eligible Afghans who helped Americans despite great personal risk to themselves and their loved ones to apply for entry into America with their families.

Eligible Afghans include interpreters for the US military as well as individuals integral to the American embassy in Kabul. While the program has existed since 2009, the number of applicants skyrocketed after the chaotic US withdrawal from Afghanistan in August 2021.

Shawn VanDiver, the president of #AfghanEvac, a coalition of organizations dedicated to helping Afghans trying to leave Afghanistan, said that though the charges are serious, "it's critical that we do not assign blame to an entire community for the actions of one individual. Thousands of Afghans who resettled in the United States are working to build new lives and contribute to our shared future."

"These are the same individuals who stood shoulder to shoulder with us in Afghanistan for over two decades, defending the values we hold dear," he said in a statement. "Now, they are our neighbors, and we must support them as they seek safety and stability in their new home."