A branch of Citibank. Citigroup Inc reported a surprise first-quarter profit of US$4.4 billion yesterday.

Citigroup's strong showing follows similarly impressive results last week by Bank of America Corp and JPMorgan Chase & Co. That has boosted hopes that the worst of the credit crisis has passed and banks may be entering a period of sustained profitability.

Yet CEO Vikram Pandit sought to dampen short-term expectations for Citigroup, saying the bank remained cautious "given the uncertain economic recovery and high unemployment in the US."

"Realistically, we do not expect our performance to follow an invariable trend-line upward," he said. "Longer-term, however, the prospects for Citigroup are clear and bright."

Pandit sounded a little less upbeat about the economy than his counterparts at JPMorgan Chase and BofA. But Citigroup's recovery from the devastation of the financial markets has been more difficult.