Three men accused in a plot to travel to Syria to join forces with the Islamic State group pleaded not guilty Friday to terrorism charges in federal court.

Abdurasul Hasanovich Juraboev, 24, Akhror Saidakhmetov, 19, and Abror Habibov, 30 were indicted this week on charges of conspiracy to provide material support to a foreign terrorist organization, conspiracy and travel document fraud. Federal officials say Juraboev and Saidakhmetov had tickets to travel to Turkey but were really going to Syria.

Saidakhmetov was arrested at Kennedy Airport late last month, where he was attempting to board a flight to Istanbul, authorities said. Juraboev had a ticket to travel to Istanbul this month, federal prosecutors said. Habibov was arrested in Florida and extradited to New York this week. He is accused of helping Saidakhmetov with his travel arrangements after Saidakhmetov's mother took his passport. The mother appeared in court, weeping, but did not comment.

Saidakhmetov's lawyer, Adam Perlmutter, said his client was very concerned but maintains his innocence.

He is "very frightened by what's happening to him," Perlmutter said.

According to court documents, Juraboev first came to the attention of law enforcement in August, when he posted on an Uzbek-language website that propagates the Islamic State ideology. His plans included attacks against President Barack Obama or planting a bomb on Coney Island, officials said.

Federal officials say Juraboev identified Saidakhmetov as a friend with a shared creed. The two exchanged messages on how to get overseas, and Saidakhmetov and an informant watched videos of Islamic State training camps in Syria, according to court papers. Prosecutors say Saidakhmetov also threatened an attack in the U.S. if he was unable to join the Islamic State group.

Saidakhmetov told the informant in September that he wanted to travel to Syria for jihad, or holy war, but that his concerned mother confiscated his passport, the complaint said. He said he would lie and tell her he planned to go to Uzbekistan instead to visit relatives. When he called to ask for his passport back, she hung up the phone. Habibov, meanwhile, agreed to help finance his trip, according to court papers.

Habibov's attorney, Eric Franz, said his client had been cut off from his family since his arrest. "My client is shocked and astonished by the allegations," he said.

Their next court date is scheduled for June 19.

The Islamic State group largely consists of Sunni militants from Iraq and Syria but has also drawn fighters from across the Muslim world and Europe. The FBI for the last year has expressed worries about the flow of Western fighters to Syria.

Saidakhmetov is a Brooklyn resident and citizen of Kazakhstan. Juraboev is a Brooklyn resident from Uzbekistan. Habibov is also from Uzbekistan and had been in the U.S. legally, but his visa had expired, officials said.