Police chiefs have made clear they are furious about the publication of confidential material in US media, including bomb site photographs in the New York Times, saying such leaks undermined relationships with trusted security allies.
British Home Secretary Amber Rudd said Wednesday that American leaks about the Manchester bombing investigation were "irritating" and that he had "been very clear with our friends that that should not happen again".
Police in Dusseldorf later confirmed that Abedi transited through the airport but remained in a secure zone. The two leaders will meet at a North Atlantic Treaty Organisation summit in Brussels later on Thursday.
The official threat level in Britain was raised after the Manchester attack to "critical", its highest level, meaning a further attack could be imminent.
British police said leaked details of the Manchester attack, including forensic photos provided to The New York Times, have hurt their investigation and that police investigating the attack have stopped sharing information with the United States, the BBC reported.
President Trump said should the individual who leaked the Manchester photographs to the New York Times be found, they "should be prosecuted to the fullest extent of the law". "When that trust is breached it undermines these relationships and undermines our investigations".
Britain routinely shares intelligence with the United States bilaterally, and also as part of the "Five Eyes" network which also includes Australia, Canada and New Zealand.
Manchester's mayor, Andy Burnham, called the USA "arrogant, wrong and disrespectful" to Manchester.
After the attack, which killed 22 teenagers and injured 50 others, victims are still identified.
Salman's older brother Ismail is among those under arrest in Britain. Abedi's father and younger brother have been detained in Libya, where they are questioned. A woman was arrested late Wednesday but was later released without charge.