The hackers stole $81 million from Bangladesh's foreign exchange account on February 5, according to officials from Bangladesh Bank, the central bank, and transferred it to the Philippines.
The hackers, who bombarded the New York bank with dozens of transfer requests, had been attempting to steal a further $850 million, but the bank's security systems and typos in some requests prevented the full theft.
"$81 million was transferred from the Federal Reserve Bank to Filipino accounts while attempts to claim $850 million were foiled by the Federal Reserve Bank's security system," Razee Hassan, deputy governor of Bangladesh Bank, told AFP.
"Attempts to transfer money to Sri Lanka by the hackers were foiled as their transfer requests contained typos," he said.
Hackers made 35 unsuccessful transfer attempts and appeared to be exploiting gaps in communication between banks at weekends, Hassan added.
The hack took place on a Friday, when Bangladesh Bank is closed, while the Federal Reserve Bank in New York is closed on Saturday and Sunday.
In the Philippines, banks were also closed on the Monday owing to Chinese New Year.
Bangladeshi cyber crime experts are investigating the incident. The Bangladesh Bank has previously said it suspects the hackers were Chinese.
The US reserve bank, which manages the Bangladesh Bank reserve account, denied its own systems were breached.
The Federal Reserve Bank of New York wrote on its Twitter account on March 7: "Regarding hacking reports, there is no evidence of attempts to penetrate Federal Reserve systems & no evidence Fed systems were compromised."
