WASHINGTON — The high-stakes battle for political positioning on Iraq is escalating between Senators Clinton and Obama as their campaigns took direct aim at each other yesterday.

The sniping, which centered on the Clinton camp’s accusing Mr. Obama of misstating Mrs. Clinton’s war stance, came just days after the Illinois senator launched his campaign and highlighted how aggressive the fight for the Democratic nomination is likely to be.

The exchange started after Mr. Obama, seeking on Monday to explain the difference between his war position and Mrs. Clinton’s, said that while both senators favored a cap in troop levels, Mrs. Clinton had not called for a “phased redeployment” to begin, as he had.

Upping the ante, the Clinton campaign wasted little time in firing off a statement yesterday titled “Fact Check.”

“Senator Obama is mistaken,” a top Clinton adviser, Howard Wolfson, said. “Senator Clinton has long been on record in favor of a phased redeployment of troops.”

The statement said both lawmakers had voted for redeployment as early as 2005 and listed several statements from Mrs. Clinton supporting the move since then.

By midafternoon, the Obama team issued a response: “Only Barack Obama opposed the war in Iraq from the start, and only Barack Obama has legislation that would, by force of law, begin a redeployment by May 1, 2007 and have all combat forces out of Iraq by March 31, 2008.”