WASHINGTON — While saying JPMorgan Chase & Co. had enough capital already to comply with new Basel III requirements, Jamie Dimon, the bank's chairman and chief executive, said Tuesday that regulators had gone too far in crafting the international capital accord.

Speaking to the Council of Institutional Investors, Dimon delivered his harshest assessment yet of Basel III, arguing that regulators are "getting extreme and excessive."

"I can't prove this right now, but for all the academics here, it will stifle economic growth," Dimon said. "I believe it already is. I believe banks around the world are deleveraging and preparing for the potential impact of Basel III … charges right now."

Under the Basel III accord, banks must hold 4.5% in common equity by 2015, and an additional 2.5% cushion by 2018. While saying JPMorgan Chase already has a 7% common equity ratio, Dimon said that Basel III has many other parts, including new liquidity requirements and a potential capital surcharge on the largest financial institutions.

Combined with changes made by the Dodd-Frank regulatory reform law, Dimon said, the system was being completely overhauled. "This is far higher capital and more liquidity, more resolution [powers for the government], more regulations, more stress tests," he said. "It's not just one change we are making. It's enormous amounts of changes. … I think just someone should take a deep breath in terms of adding more capital right now at this point."

Dimon also touched on continuing negotiations between the top five mortgage servicers, the 50 state attorneys general and several federal agencies to resolve problems with the foreclosure process.

He acknowledged that mistakes, such as robo-signing, were "embarrassing." "It should never have happened," he said.

But Dimon denied that it had resulted in improper foreclosures and said the end result had been to prolong the foreclosure process.

"We made a mistake and we are going to pay for that mistake," he said. "We are slowing down the whole process. The other thing you should think about is slowing down the process is not going to do anything for our communities. … We are working, though. We are going to have a lot of regulatory, a lot of legal [issues] and you've read about the state AGs. We all hope we get it done, but get it done right."