Cryptocurrencies were lower in early trade Tuesday - possibly reacting to comments from former U.S. President Donald Trump. Trump says bitcoin is a "scam against the dollar" that needs "very, very high regulation."

"Bitcoin, it just seems like a scam," Trump said. "I don't like it because it's another currency competing against the dollar. I want the dollar to be the currency of the world. That's what I've always said." He insisted cryptocurrencies should be regulated "very, very high."

Bitcoin was last traded at $32,737.89 compared with $32.141.00 a day earlier - down 1.82%. About $36.8 billion of the tokens were traded in the past 24 hours up to midmorning Asia time (23:20 hours Monday EST). Ethereum was trading down 10.92% at $2,483 32 coin compared with $2,787.67 24 hours earlier on trades of $32.2 billion. Trending Dogecoin was down 5.8% at $0.32 compared with $0.37 a day earlier on trades of $3.4 billion.

Market participants are considering another volatile week for cryptocurrencies. A Goldman Sachs survey out over this past weekend said chief investment officers considered bitcoin their least favorite investment.

The world's No. 1 cryptocurrency has had a volatile few months and moved even lower following reports China's social media company Weibo suspended a number of cryptocurrency accounts. The People's Bank of China warned against using cryptocurrency for payments. Last month, China's State Council or cabinet, promised to crack down on bitcoin mining and trading, escalating a campaign against cryptocurrencies days after three industry bodies banned crypto-related financial and payment services.

The official Xinhua News Agency has published articles that exposed a series of crypto-related scams. State broadcaster China Central Television has said cryptocurrency is a lightly regulated asset often used in black market trade, money laundering, arms smuggling, gambling and drug dealings.

The stepped-up crackdown also comes as China's central bank is accelerating testing of its own digital currency.

Meanwhile, the Basel Committee on Banking Supervision will consult on how lenders should shield themselves from cryptocurrency assets, it said this week as regulators turn up the heat on a growing but risky investment sector.

"While banks' exposures to cryptocurrency assets are currently limited, the continued growth and innovation in cryptocurrency assets and related services, coupled with the heightened interest of some banks, could increase global financial stability concerns and risks to the banking system in the absence of a specified prudential treatment," it said.

The committee will publish its consultation paper this week.

HSBC, Europe's biggest bank, told Reuters last month that it had no plans to join rival lenders such as Goldman Sachs in launching a cryptocurrency trading desk or offering the digital coins, saying they are too volatile and lack transparency.

The Bank of England has said investors should be prepared to lose all of their money if they invest in cryptocurrencies.