Well, the calls to end "bank-on-bank violence" don't appear to be going well.

In an interview with CNBC's "Squawk Box" Wednesday, JPMorgan Chase Chief Executive Jamie Dimon had tough words — and a petty insult — for Camden Fine, head of the Independent Community Bankers of America.

Dimon was asked on air about an op-ed he wrote last month for The Wall Street Journal, in which he argued that all members of the banking industry should work together as friends, not enemies. Community banks "depend on large banks" to provide them a range of services from investments to international payments, he wrote in the op-ed.

Fine took aim at the op-ed shortly after it was published. "Just because Jamie Dimon says 'let's sing kumbaya' doesn't mean community banks are going to line up like a Greek chorus," he said in an interview with Bloomberg News.

Dimon's response?

"I think the guy who wrote that is a jerk, OK?" he said on CNBC.

The nationally televised interview laid bare the ongoing tensions between large and small banks, despite the ongoing calls to put an end to industry infighting.

The American Bankers Association in particular has made an effort over the past year to end what ABA CEO Rob Nichols described as "bank-on-bank violence."

"We'll have more influence and clout working together rather than being segmented," Nichols said in an interview last fall with American Banker.

Dimon hasn't always practiced the restraint that he has recently preached. Defending JPMorgan's size and scope, Dimon described small banks as "risky" in his shareholder letter last year, noting that many of them failed during the financial crisis.

What's curious about Wednesday's exchange is that both Dimon and Fine took digs at each other, while at the same time calling for an end to the intraindustry bickering.

During the interview, Dimon noted that the $2.4 trillion-asset JPMorgan provides banking services to more than 800 regional banks. He also described the relationship between big and small banks as "symbiotic."

The ICBA, to say the least, disagreed.

In a press release this afternoon, Fine took aim at Dimon, saying that megabanks have failed to take responsibility for the financial crisis.

He also said that JPMorgan has a competitive advantage over small banks because it has a guaranteed backstop of "emergency infusions of taxpayer funding."

And, as a finishing touch, Fine described the calls to end "bank-on-bank violence" as "the new mantra of the 'too big to fail' banks and their hired-gun trade representatives."

So much for kumbaya indeed.

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