A man has been arrested near the US Capitol building as part of an anti-terror investigation, US officials say.
Amine El Khalifi, 29, of Alexandria, Virginia was taken into custody by the FBI.
Officials told US media the man thought he was heading to carry out a suicide attack on the Washington DC building, home to the US Congress.
He was "closely and carefully monitored" for weeks, according to the FBI and US Capitol police.
Authorities say the public was never in any danger.
Mr Khalifi allegedly thought undercover FBI agents he was working with were members of the al-Qaeda network.
However, he was not believed to have any known existing connections to al-Qaeda, officials said.
Mr Khalifi was said to have overstayed a visitor visa for years, and was under investigation for more than a year, according to the Associated Press news agency.
He carried a v
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