SINGAPORE (Reuters) - U.S. Treasuries extended heavy losses on Wednesday in a sign investors are selling even their safest assets as a global market rout unleashed by U.S. tariffs takes an unnerving turn towards distress and a dash for the safety of cash.

"This is beyond fundamentals right now. This is about liquidity," said Jack Chambers, senior rates strategist at ANZ in Sydney.

The 10-year U.S. Treasury yield, the globe's benchmark safe-haven anchor, was up 20 basis points and rising in Asia - a remarkable move in a time zone where it's usually fairly steady.

At 4.46% the yield is up 59 basis points from Monday's low, with traders saying hedge funds were the heaviest sellers as they started to be forced from leveraged bets that in calmer times profit from small gaps between cash and futures prices.

"This kind of thing becomes problematic if the prime broker starts saying that now ... I want to charge you a higher margin or I basically want more margins from you," said Mukesh Dave, chief investment officer at Aravali Asset Management, a global arbitrage fund based in Singapore.

Thirty-year U.S. yields spiked 24 bps to 4.9553% and the three-day move in yield - if sustained - would mark the heaviest selloff in the long end since 1981.

Selling was heavy in Japan and Australia.