The report says two pieces of information came to MI5 indicating possible criminal activity by Abedi, but this wasn't judged to be related to possible terrorist acts.
The head of MI5, Andrew Parker, is believed to have briefed Cabinet ministers about the alleged terror plot on Tuesday.
Naa'imur Zakariyah Rahman, 20, and Mohammed Aqib Imran, 21, were due in court on terror charges on Wednesday.
Scotland Yard, military intelligence security service MI5 and West Midlands Police reportedly had been investigating the plot for "several weeks".
A plot to assassinate UK Prime Minister Theresa May has been foiled, Sky News reported on Tuesday.
United Kingdom authorities think they've arrested two men who plotted to kill Prime Minister Theresa May after "bomb (ing) their way into" her official residence, the Guardian reported.
Jerusalem Is 'Red Line' for Muslims: Turkey's Erdogan
Jerusalem is our capital, and the time has come for the world to recognize this. "We are imploring the USA once again". "Unfortunately, Erdogan does not miss an opportunity to attack Israel ", he said in a statement.
Pizza Hut testing beer and wine delivery
Pizza Hut's beer delivery menu in Phoenix includes six packs of Budweiser, Bud Light, Shock Top and Kilt Lifter, a local brew. Want some beer with your pizza? The company would not reveal to CNN which cities will be next to get delivery service.
Chester Bennington autopsy reveals small amounts of alcohol and ecstasy
A boarding pass from Bennington's flight the previous day was still in his pocket at the time of his death. In the report, the coroner wrote, "autopsy findings are characteristic of suicidal hanging".
Suicide bomber Salman Abedi detonated an explosive at an Ariana Grande concert that killed 22 people on May 22.
A man died in a terrorist incident at Finsbury Park mosque in north London in the same month - and, in September, an attempt to bomb a Tube train at Parsons Green station failed.
Stringent protective measures were first put in place in the 1970s, and were tightened during the 1980s when Irish republicans launched attacks on the British mainland. The device landed in the back garden.
The nearest the IRA got to killing a British prime minister was in 1984 when they targeted the hotel Margaret Thatcher and top officials were staying in for that year's annual Conservative party conference in Brighton on Britain's south coast.