US President Barack Obama has proposed significant new curbs¹ on the activities of banks to try to prevent future financial crises.

美国总统奥巴马提议对银行活动进行调控以避免将来可能出现的金融危机。

The plans - the most far-reaching yet -include limits to the size of banks and restrictions² on riskier³ trading.

"Never again will the American taxpayer⁴ be held hostage by banks that are too big to fail," Mr Obama said.

He added he was ready for a "fight" with any banks prepared to lobby游说 against tougher regulations.

US stocks such as JP Morgan Chase and Bank of America fell sharply as the sweeping⁵ planned reforms were announced.

JP Morgan lost 6.6%, while Bank of America gave up 6.2%.

Limiting risk taking

"While the financial system is far stronger today than it was one year ago, it is still operating under the exact same rules that led to its near collapse," Mr Obama said.

His proposals also include a ban on retail⁶ banks零售银行 from using their own money in investments - known as proprietary⁷ trading. Instead, banks would be limited to investing their customers' funds.

"Banking⁸ reforms do not come bigger than those proposed by President Obama," the BBC's business editor Robert Peston said.

This may mean that some of the US' biggest banks, such as Bank of America and JP Morgan, whose shares were badly hit, may have to be broken up.

The industry lobby group for banks suggested Mr Obama was trying to return the US to the past.

"The better answer is to modernise⁹ the regulatory framework规章制度 and not take the industry and the economy back to the 1930s," said the Financial Services Roundtable, an industry group that represents large Wall Street institutions.

In the UK, shadow chancellor影子大臣 George Osborne said that if the Conservatives won the next general election, they would impose an identical dismantling¹¹ of UK banks to those suggested by the US president.

City Minister Lord Myners said the US proposals were "very much in accordance with the direction we have been setting".