NEW YORK: Federal authorities arrested two men on Friday in connection with the case of an Afghan-born man accused of plotting a bombing attack in New York City on the anniversary of the Sept. 11 attacks.

Adis Medunjanin, 25 and of Bosnian origin, and Zarein Ahmedzay, 24, were arrested in New York City as part of the investigation of Najibullah Zazi, 24, an FBI spokesman said.

The New York Times reported they are suspected of traveling with Zazi in 2008 to Peshawar, Pakistan, where prosecutors allege Zazi received Al-Qaeda training on how to make bombs.

Zazi, a former coffee vendor from New York who had moved to Colorado, was indicted by a federal grand jury in September on a charge of conspiracy to use weapons of mass destruction.

Security experts considered the Zazi case among the most serious within US borders since the attacks of Sept. 11, 2001, though in recent weeks the case was overshadowed by the attempted Christmas Day bombing of a Detroit-bound airliner.

The Zazi case was so alarming because it alleges a young man who grew up largely in the United States became radical, traveled overseas for Al-Qaeda training, and then took steps toward carrying out an attack back home.

The two new suspects attended high school together with Zazi in the New York City borough of Queens, a lawyer for Medunjanin said.

Medunjanin and Ahmedzay were due to appear later on Friday in federal court in Brooklyn. They were arrested after Medunjanin got into a car accident and tried to flee the scene on foot, said Richard Kolko, an FBI spokesman. He was arrested after being taken to the hospital, Kolko said.

Robert Gottlieb, an attorney for Medunjanin, complained that he was denied access to his client after the accident.

“We have finally been told that my client is in custody after far too long of being deprived of access to him,” Gottlieb said.

Gottlieb said Medunjanin’s Queens home had been searched by law enforcement in September and said computers and other items had been seized.

He declined to comment on media reports that Medunjanin had been to a training camp with Zazi but did say the two men went to high school together. “At this point, I am not discussing the facts of the investigation,” he said.

Prosecutors allege Zazi took a bomb-making course at an al Qaeda training camp in Pakistan, had bomb-making notes on his laptop, and acquired bomb-making materials similar to those used in the 2005 attacks in London’s transit system.

Authorities say they observed Zazi buying large quantities of acetone and hydrogen peroxide at beauty supply stores in Colorado. No chemicals or any bombs were recovered.

The FBI had other suspects under surveillance since then, though none of them had been identified until Friday’s arrests.

Zazi’s father and a New York imam have also been arrested in the case, accused of lying to federal authorities.