SINGAPORE (BLOOMBERG) - Bitcoin struggled to hold above the closely watched US$20,000 level, extending a period of marked volatility that saw huge weekend swings.

The largest cryptocurrency fell as much as 4.8 per cent to US$19,618 on Monday (June 20) in Asia and was trading at US$20,036 as at 12.30pm in Tokyo.

Ether at one point shed 7.8 per cent but held above US$1,000.

Solana, Cardano and Dogecoin were in the red.

Bitcoin sank almost 15 per cent on Saturday but then vaulted back above US$20,000 with a 16 per cent surge on Sunday. The pattern of swings suggest investor sentiment remains highly fragile as the United States Federal Reserve goes full-throttle to fight inflation with interest rate hikes that drain liquidity from markets.

"Expect more pockets of forced selling of Bitcoin and Ether as the market figures out who is swimming naked," Arthur Hayes, co-founder of crypto exchange BitMEX, said on Twitter.

He said he does not know if the selling is over but "for those skilled knife-catchers, there may yet be additional opportunities to buy coin from those who must whack every bid no matter the price".

Some crypto executives argue that Bitcoin below US$20,000 could lead to more liquidations of leveraged positions. The token is down about 57 per cent since the start of the year, while others have suffered even more.

The T3 Bitcoin Volatility Index, a measure of the token's expected 30 day-volatility, has jumped towards the highs of 2022.

Adding to the uncertainty is the intense pressure on decentralised finance applications.

Their popularity soared as a source of high yields when pandemic-era stimulus drove a record-breaking crypto boom.

But now they are taking unprecedented measures to protect themselves against cascading liquidations.

Embattled crypto lending platform Celsius Network said on Monday it needs more time to stabilise its liquidity and operations after freezing deposits last week.