His latest medical trip came as the country's health workers embarked on a nationwide strike to seek better working conditions, triggering criticism from the opposition and a segment of society.
His office said on Monday that his doctor had requested to see Buhari and the president would return home on Saturday.
Top Diplomats From Britain, France, Germany to Discuss Iran Deal
Meanwhile, thousands took to the streets of the Iranian capital after Friday's morning prayers to rally against U.S. and Israel. Trump said Iran was not living up to the deal, citing Iranian documents that Israel said it stole from Iran earlier this year.
The disclosure had "put to rest speculation on the health status of the president, as well as his attendant inability to effectively govern". "He can't travel for an official meeting to the United States and sneak into London to see his doctor, then tell Nigerians it was a technical stopover due to flight issues".
Buhari departed Abuja for London on Tuesday for the routine medical check-up.
Democrats in tough reelection battles distance themselves from Washington
Hupfer said the party has not seen any erosion of support for Trump since he won the state over Hillary Clinton in 2016. Now, it has dropped to 38 percent , only five percent more favorable than the Republican Party.
"Mr. President was earlier scheduled to return tomorrow", said Bashir Ahmad, a presidential spokesman, posting a video on Twitter showing Buhari disembarking from his presidential jet.
It is not yet known what informed it as the presidency was yet to issue an official statement concerning his return at the time of this report.
Tesla crash that killed 2 teenagers is under NTSB investigation
All about three occupants from the auto involved from the wreck Tuesday nighttime at Fort Lauderdale have been 18-year-old males. The agency is also investigating another Tesla-related fire after a Model X SUV crashed on a freeway in California in March .
Also, that President Buhari was the first sub-Saharan African Head of State to visit the Trump White House.