Federal officials say the public was never in danger in a Massachusetts man's alleged plot to blow up the Pentagon and the U.S. Capitol using remote-controlled airplanes filled with explosives.

They say the explosives delivered to Rezwan Ferdaus were always closely monitored.

The 26-year-old was arrested Wednesday and accused of plotting to blow up the Pentagon and U.S. Capitol, as well as attempting to assist Al Qaeda in attacking U.S. troops overseas.

Rezwan Ferdaus of Ashland, Mass., was arrested Wednesday in Framingham after undercover FBI agents delivered weapons Ferdaus allegedly sought for the alleged plan. The stash included what he thought was 25 pounds of C-4 explosives, as well as three grenades and six fully-automatic AK-47 assault, a press release from the Department of Justice reads.

Ferdaus was arrested after he took the materials and locked them in his storage unit, according to an affadavit that says the storage unit was rented under a false name in June.

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The public was never in danger from the explosives, as undercover agents monitored the alleged plot and kept up frequent contact with Ferdaus, the press release read. More than 30 federal, state and local agencies in the FBI's Joint Terrorism Task Force worked together in the operation, including police departments in Worcester, Ashland and Framingham and the ATF.

In recorded conversations, Ferdaus said he planned to attack the Pentagon and U.S. Capitol using aircraft similar to “small drone airplanes” that were guided by GPS equipment, the affidavit said. The plan called for three remote-controlled aircraft to carry out the attacks, along with six other gunmen divided into two teams, with Ferdaus coordinating the operation.

In May, Ferdaus traveled from Boston to Washington, D.C., to take photos of the Pentagon and Capitol for surveillance. He planned to launch the C4-filled aircraft from sites at the East Potomac Park, authorities allege, and an F-86 Sabre remote-controlled aircraft was delivered to Ferdaus’ storage facility in August.

Authorities say they gave Ferdaus multiple opportunities to back out of the plot, as they told him it would likely kill women and children. But Ferdaus never wavered in his plan, the affidavit said.

"I just can't stop; there is no other choice for me," he allegedly said.

Ferdaus, who graduated Northeastern University in 2008 with a degree in physics, is accused of beginning in early 2010 a plot to bring violent “jihad” against the U.S, who he described as "enemies of Allah."

Ferdaus is also accused of supplying eight mobile phones to undercover FBI agents who he thought were recruiters for Al Qaeda. The phones were modified to be used as electrical switches for IEDs, and Ferdaus thought they could be used to kill American soldiers, the affidavit said. Ferdaus also allegedly made a training video to demonstrate how to make more the weapons.

Ferdaus said “that was exactly what I wanted,” when he was told one of the devices killed three U.S. soldiers and injured four to five others in Iraq in June, authorities said.

Renata Nyul, director of communications at Northeastern University, said in a statement that "We have more than 200,000 alumni living and working around the world. It is inappropriate for the university to comment on a pending investigation involving one of its graduates."

Ferdaus faces up to 15 years in prison if convicted of providing material support and resources to a foreign terrorist organization, up to 20 years for a charge of attempting to destroy national defense premises. He also faces a five-year minimum mandatory prison sentence and up to 20 years if convicted of attempting to damage and destroy U.S.-owned buildings with explosives.

He was expected to appear Wednesday afternoon in federal court in Worcester, Mass.

"I want the public to understand that Mr. Ferdaus' conduct, as alleged in the complaint, is not reflective of a particular culture, community or religion," said Carmen Ortiz, U.S. Attorney for the District of Massachusetts. "In addition to protecting our citizens from the threats and violence alleged today, we also have an obligation to protect members of every community, race and religion against violence and other unlawful conduct."

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