The price of bitcoin dropped Thursday as investors began shedding risk amid an equity markets decline. Fears of a slowing global economic comeback caused by the potential spread of the Covid-19 delta variant appeared to be behind investors move into safer assets like Treasurys.

Bitcoin fell below $32,500 around 4:00 a.m. EST Thursday but has been climbing slowly since then. It’s currently trading at $33,000, down 4% on the day according to Coin Metrics. Most other cryptocurrency assets are falling with it, including ether, which is trading 8.7% lower at $2,150.

That backslide came around the time of reports Japan has declared a state of emergency in Tokyo for the upcoming Olympics based on a potential rebound in Covid-19 cases. Stock futures fell on the news, and companies that would benefit from an economic rebound declined in early trading. The 10-year Treasury yield also dropped to 1.25%.

Sen. Elizabeth Warren, D-Mass., warned against the growing risks the “highly opaque and volatile” cryptocurrency market poses to consumers and financial markets in a letter to Securities and Exchange Commission Chairman Gary Gensler.

Bitcoin has struggled to reclaim its May highs. Its price has been hovering in the $30,000 range, down from its all-time high of $65,000 it reached in April. Some traders see bitcoin going higher in the long-term despite some near-term headwinds. Still, some say it could fall as low at $20,000 before institutional investors get back into it.

“We’re consolidating in here between [$30,000 and