* ECB minutes reveal concerns over currency overshoot; sink euro
* Dollar volatile after rumors of Cohn resignation
* Barcelona attack boosts safe-haven yen and franc
* Graphic: World FX rates in 2017 http://tmsnrt.rs/2egbfVh (Updates to afternoon U.S. trading, adds quote, data)
NEW YORK, Aug 17 (Reuters) - The dollar rose on Thursday, boosted by weakness in the euro after the European Central Bank's July policy meeting minutes, but the U.S currency was volatile as rumors swirled about the possible resignation of Gary Cohn, director of the U.S. National Economic Council.
Following rumors of Cohn's departure, the White House released a statement saying he "intends to remain in his position."
That helped calm markets as Cohn, along with Treasury Secretary Steve Mnuchin, is seen as pivotal to U.S. President Donald Trump's economic agenda of tax cuts and infrastructure spending.
Still, analysts said, the dollar was in an unenviable position, with inflammatory news headlines from the White House weighing on its already weak position.
"We had yesterdays Fed minutes that certainly didnt do the dollar any favors," said Omer Esiner, chief market analyst at Commonwealth Foreign Exchange in Washington.
The dollar fell on Wednesday after the release of minutes from the Federal Reserve's July policy meeting that showed policymakers growing more worried about weak U.S. inflation.
"We have to look at it in that context, where the dollar's already on a somewhat shaky footing," Esiner said.
The currency whipsawed for most of the day as news about Cohn and an attack in Barcelona that left at least 13 dead sent traders to safe-haven currencies like the Japanese yen and Swiss franc.
The dollar fell 0.55 percent against the yen to 109.60 yen and 0.4 percent against the Swiss franc. It hit session lows against both in the aftermath of the Barcelona attack.
The dollar index edged up to 93.628.
The index's largest component is the euro, which sank to a three-week low after the ECB's minutes showed officials warning about a possible market overshoot for the currency. The euro has risen close to 12 percent against the dollar this year.
The minutes, released at 7:30 a.m. EDT (1130 GMT), spurred an almost 1 percent fall in the single currency against the dollar, along with losses against the Swiss franc, yen and sterling.
The euro was last down 0.25 percent against the dollar at $1.1736.
Analysts said the snapback in the euro may have also been due to the market over-reacting to the ECB minutes and thin trading volume.
"Given the market rumors, given the anxiety, given the market positioning, this seems to be a reasonable price action," said Marc Chandler, global head of currency strategy at Brown Brothers Harriman.
(Reporting by Dion Rabouin; Editing by Chizu Nomiyama and Dan Grebler)