A solid down day in crypto is morphing into a plunge after Federal Reserve Chairman's unexpectedly hawkish remarks at his post-policy meeting press conference.

"A rate cut in December is far from a foregone conclusion," said Powell in his opening remarks. That was a shock to markets, which had priced in a 90% chance of another rate cut at the Fed's final meeting of the year.

The effect in prices was immediate, with bitcoin BTC$113,421.04 tumbling about $2K to the current $109,600, now lower by 5% over the past 24 hours and largely having given up its big gains from earlier in the week.

Stocks also headed lower on Powell's remark, moving from a modest advance for the day to a modest loss. The 10-year Treasury yield has now jumped 8% basis points to 4.06% and the dollar is surging higher. The odds of a December rate cut have dropped to just 69% from 90% earlier, per CME FedWatch.

Whether Powell is just trotting out a tough line — as Fed officials often do — or whether he really believes the central bank will return to wait and see mode, remains to be seen.

The central bank minutes earlier, as expected, had trimmed its benchmark fed funds rate by 25 basis points to 3.75%-4.0%. The cut, though, was kind of a hawkish one, if that's possible, with Kansas City Fed chief Jeffrey Schmid breaking with his colleagues and voting to hold policy steady.

The ongoing government shutdown and economic data blackout puts the central bank in a tough spot, with policymakers remaining cautious about signaling further cuts that could spark volatility in risk assets, said Marcin Kazmierczak, co-founder of oracle network RedStone.

"The shutdown’s data blackout means subsequent Fed moves are now unpredictable, and that’s what markets hate most," he said in an emailed note. "This uncertainty likely means bitcoin and broader crypto volatility through year-end."

Paul Howard, director at crypto trading firm, noted that BTC is still holding trying to hold the $110,000-$120,000 range, but concerns of a further cut potentially not happening have moved prices slightly lower.

"My sense is this is convenient for short term accumulation and we will see macro improvements heading into November driving risk assets before some end of year consolidation," he added.