Ahmad Rahami
Ahmad RahamiReuters

Federal prosecutors on Tuesday charged the Afghan-born man arrested after weekend bombings in New York and New Jersey with four counts including use of weapons of mass destruction and bombing a place of public use, Reuters reports.

The charges were laid out in a federal complaint that said a handwritten journal was found on the suspect, Ahmad Khan Rahami, that praised former Al-Qaeda leader Osama bin Laden and accused the U.S. government of slaughtering Islamist fighters in Afghanistan, Iraq, Syria and “Palestine”.

Rahami was apprehended in Linden, New Jersey, after a firefight on Monday – two days after bombs exploded in the Chelsea neighborhood of Manhattan and in Seaside Park, New Jersey.

The federal charges against him come after his father said he had reported concerns about his son being involved with terror to the Federal Bureau of Investigations (FBI) two years ago.

The FBI acknowledged it had investigated Rahami in 2014, but found no "ties to terrorism" and dropped its inquiry.

The White House said on Tuesday it appeared that the bombings were "an act of terrorism" as an investigation continued in to whether Rahami had accomplices, or if he picked up jihadist Islamic views during trips to Afghanistan and Pakistan.

"The investigation is active and ongoing, and it is being investigated as an act of terror," U.S. Attorney General Loretta Lynch said in Lexington, Kentucky, according to Reuters.

Rahami suffered multiple gunshot wounds during the shootout with police prior to his arrest. He was listed in critical but stable condition, and police had not yet been able to interview him in depth, New York Police Department Commissioner James O'Neill said.

Two U.S. officials told Reuters on Tuesday that Rahami had traveled to Afghanistan and to Quetta, Pakistan, a city where support for the Taliban is significant.

The official, and other U.S. security sources, said Rahami underwent additional security screening upon returning from abroad but passed each time. One of the officials, who specializes in counter-terrorism, said the "secondary" screening included asking Rahami where he had gone and for what purpose.

Rahami's wife left the United States a few days before the bombings, CNN reported, citing a law enforcement source.