FTX filed for bankruptcy on Friday after traders rushed to withdraw $US6 billion ($A9 billion) from the platform in just 72 hours and rival exchange Binance abandoned a proposed rescue deal.
FTX Chief Executive John J. Ray III said on Saturday that the company was working with law enforcement and regulators to mitigate the problem, and was making "every effort to secure all assets, wherever located".
"Among other things, we are in the process of removing trading and withdrawal functionality," he said.
FTX's dramatic fall from grace has resulted in 30-year-old Bankman-Fried, known for his shorts and T-shirt attire, morphing from being poster child of crypto's successes to the protagonist of the industry's biggest crash.
Bankman-Fried, who lives in the Bahamas, has also been the subject of speculation about his whereabouts.
On Saturday he told Reuters that he was in the Bahamas, denying speculation on Twitter that he had flown by private jet to South America.
At least $US1 billion of customer funds have vanished from the platform, sources told Reuters on Friday.
The firm's founder Sam Bankman-Fried had transferred $US10 billion of customer funds to his trading company, Alameda Research, the sources said.
New problems emerged on Saturday when FTX's US general counsel Ryne Miller said in a tweet that the firm's digital assets were being moved into so-called cold storage "to mitigate damage upon observing unauthorised transactions".
Cold storage refers to crypto wallets that are not connected to the internet to guard against hackers.
Blockchain analytics firm Nansen said it saw $US659 million in outflows from FTX International and FTX US in the last 24 hours.
A separate blockchain analytics firm Elliptic said that about $US473 million worth of cryptoassets were "moved out of FTX wallets in suspicious circumstances early this morning" but that it could not confirm that the tokens had been stolen.
Crypto exchange Kraken said: "We can confirm our team is aware of the identity of the account associated with the ongoing FTX hack, and we are committed to working with law enforcement to ensure they have everything they need to sufficiently investigate this matter."
FTX was not immediately available for comment about the outflows or Kraken's statement.
A document that Bankman-Fried shared with investors on Thursday and was reviewed by Reuters showed FTX had $US13.86 billion in liabilities and $US14.6 billion in assets.
However, only $US900 million of those assets were liquid, leading to the cash crunch that ended with the company filing for bankruptcy.
In its bankruptcy petition, FTX Trading said it has $US10 billion to $US50 billion in assets, $US10 billion to $US50 billion in liabilities, and more than 100,000 creditors.
Ray, a restructuring expert, was appointed to take over as CEO.
The collapse shocked investors and prompted fresh calls to regulate the cryptoasset sector, which has had losses stack up so far this year as cryptocurrency prices collapsed.
"Things will continue to simmer after the FTX crash," Alan Wong, operations manager of Hong Kong Digital Asset Exchange, said.
"With a gap of $US8 billion between liabilities and assets, when FTX is insolvent, it will trigger a domino effect, which will lead to a series of investors related to FTX going bankrupt or being forced to sell assets. In an illiquid bear market, the event will lead to a new round of cryptocurrency declines, as well as a liquidation of leverage."
Since its founding in 2019, FTX had raised more than $US2 billion from top investors including Sequoia, SoftBank, BlackRock and Temasek.
In January, FTX had raised $US400 million from investors at a $US32 billion valuation.
SoftBank and Sequoia Capital said they were marking their investments in FTX down to zero.
