U.S. federal authorities say they have arrested a person near the U.S. Capitol building who they say was seeking to carry out a terrorist attack.

Officials say the suspect had sought to use what he thought were explosives in an attack on the Capitol. Law enforcement authorities say the explosives had been “rendered inoperable by law enforcement and posed no threat to the public.”

The U.S. Capitol Police say the person was detained Friday in the area of the Capitol as part of a “lengthy and extensive operation” with the FBI.

The arrest comes one day after a Nigerian man was sentenced in the U.S. to life in prison for trying to bring down an Amsterdam-to-U.S. flight on Christmas Day 2009 with explosives hidden in his underwear. U.S. officials blame Umar Farouk Abdulmutallab's plot on the Yemen-based branch of al-Qaida.