The man, who was arrested near the US Capitol building in Washington DC Friday as part of an anti-terror investigation, had been married to a Bulgarian woman.

The information was reported by a number of Bulgarian media such as Standard daily and Darik radio, citing Associated Press.

According to the United States Capitol Police, the "arrest was the culmination of a lengthy and extensive operation during which the individual was closely and carefully monitored." The investigation had been conducted jointly with the FBI, and the public was never in any danger.

Amine El Khalifi, 29, is said to be an illegal immigrant originally from Morocco, BBC further reports, noting that US officials say he was heading to carry out a suicide attack on the Washington DC building, home to the US Congress.

US officials, however, have stressed that he was not believed to have any genuine connections to al-Qaeda.

Meanwhile, as reported by Bulgarian media, the landlord of an apartment building in Arlington, Virginia, had warned police about Amine El Khalifi a year and a half ago.

Landlord, Frank Dynda, describes him as obnoxious and belligerent and says it took a court order to evict him out of his building. He also says a Bulgarian woman, believed to be Khalifi's wife rented the place and he later moved in.

"He was hostile and mentioned to me that he was not paying a dime of rent and there was nothing I could do about it. He also threatened to physically harm me. I also mentioned that I thought he was doing something suspicious in his apartment, like making bombs," Dynda is quoted saying.

Khalifi made a brief court appearance and was charged with attempting to use a weapon of mass destruction against US property - a charge that carries a maximum penalty of life in prison.

A bail hearing is set for Wednesday.

According to BBC, the suspect was said to have overstayed a visitor visa since 1999, and was under investigation for more than a year.

He carried a vest he thought was packed with explosives, reports said, but had in fact been supplied and made harmless by undercover agents. He was also carrying a gun that did not work.

Khalifi was arrested in a parking garage a few blocks from the Capitol as he made his way towards Capitol grounds.

According to an FBI affidavit, Khalifi met other individuals at the Arlington apartment in January 2011, at which he agreed with a statement that the "war on terrorism" was a "war on Muslims" and said the group had to be ready for war.

He considered other targets for an attack including an office building in Alexandria and a Washington restaurant, before switching his sights to the Capitol, the affidavit further reads.