An Ohio man claiming sympathy with Islamic State militants and charged with plotting to attack the US Capitol said in a television interview that he would have shot President Barack Obama in the head.

Christopher Cornell, 20, told Cincinnati's FOX 19 WXIX TV that if he had not been arrested by FBI agents in January, he would have carried out an alleged plot to plant pipe bombs on the Capitol and at the Israeli Embassy.

‘What would I have done? I would have took my gun, I would have put it to Obama's head and I would have pulled the trigger,’ Cornell, of Cincinnati, said in a telephone interview from the Boone County, Kentucky, jail aired on Friday.

‘Then I would have released more bullets on the Senate and the House of Representative members, and I would have attacked the Israeli Embassy and various other buildings full of kafir (a Muslim term for infidel) who want to wage war against us Muslims and shed our blood. That's what would happen,’ he said.

Cornell was arrested after he researched how to make pipe bombs, purchased a rifle and ammunition and made plans to travel to Washington to carry out the plot, according to court testimony from an FBI informant.

He is being held without bail. The charges include attempted murder of government officials, possession of a firearm to commit a crime and solicitation to commit a violent crime.

‘I got orders from the brothers overseas because I'm with the Islamic State. My brothers over there, in Syria and Iraq, gave me specific orders to carry out jihad in the West, so I did so,’ Cornell said.

Islamic State militants rule a self-proclaimed caliphate in parts of Iraq and Syria. The Federal Bureau of Investigation and the Department of Homeland Security warned police on Thursday about U.S. youths wanting to join the Islamic State in the Middle East.

Cornell began plotting the attack in August, according to his indictment. He was arrested after he posted on Twitter that he supported Islamic State.

According to court documents, Cornell met with an FBI informant to discuss his plans.