Profit after taxation dived to £190 million ($245 million, 225 million euros) in the first three months of 2017.
Profit after taxation dived to £190 million ($245 million, 225 million euros) in the first three months of 2017 after taking a vast £884-million charge on its Africa unit, Barclays said in a statement.
However, group pre-tax profit excluding exceptional items more than doubled to £1.68 billion, aided partly by deep cost-cutting and the sale of non-core assets.
"This has been another quarter of strong progress towards the completion of the restructuring of Barclays," said Chief Executive Jess Staley in the earnings release.
"Group profit before tax more than doubled ... and our core businesses continued to perform very well."
Barclays had revealed earlier this month that Staley -- who was appointed two years ago to repair the lender's reputation -- was facing a probe by British regulators and a significant pay cut after he tried to uncover the identity of a whistleblower.
The 60-year-old American has demanded the highest ethical standards from staff at the troubled bank, which faced massive fines in recent years over foreign exchange and Libor interest rate rigging scandals.
However, the bank now faces shareholder pressure over Staley's conduct, with an advisory group urging investors to abstain from backing his re-election at its upcoming annual general meeting in May.
The Barclays board has already accepted Staley's apology and his explanation that he did not know he was not allowed to try and identify the whistleblower.
Barclays did however issue a formal written reprimand to Staley, in light of the serious nature of the matter -- and will make a "very significant compensation adjustment" to his pay.
An anonymous letter was sent to board members last year raising concerns about a senior employee who had recently been recruited, including issues of a personal nature.
Staley requested that the bank's Group Information Security (GIS) team find who wrote the letter
The board found out about Staley's actions earlier this year and instructed an external law firm to investigate, as well as informing British regulators.