BAGHDAD — Iranian forces helped plan one of the most sophisticated militant assaults of the Iraq war — a January raid in which gunmen posed as an American security team and launched an attack that killed five U.S. soldiers, an American general said Monday.

U.S. military spokesman Brig. Gen. Kevin J. Bergner also accused Iran of using its Lebanese ally, the Shiite militia Hezbollah, as a "proxy" to arm Shiite militants in Iraq.

The claims were an escalation in U.S. accusations that Iran is fueling Iraq's violence, which the government in Tehran has denied. It was also the first time the U.S. military has said Hezbollah has a direct role — which, if true, would bring a dangerous new player into Iraq's conflict.

A Utah mother of one of the soldiers killed in the January attack said Monday that the news of Iran's involvement doesn't change her opinion about the war in Iraq or her position on what to do about Iran's alleged involvement in Iraq.

"My reaction basically is, we need to come home," Kathleen Snyder said in a phone interview.

Snyder's son, Army reservist Capt. Brian S. Freeman, 31, of Temecula, Calif., was killed in the attack. Freeman was also a bobsled and skeleton athlete who trained in Utah.

"No, we shouldn't invade Iran — no, we shouldn't invade Hezbollah," Snyder added. "I think we need to come home.

"I have always been against this war," she continued. "I feel there was no justification for it. Iraq did not invade the United States...There was no reason to invade them."

Snyder said her son did not support the war either, adding that, "He went — as many do — because he made a commitment early in his life, and he was fulfilling it."

Snyder said that prior to the news Monday, her husband and Freeman's stepfather, Albert Snyder, wrote a letter to Sen. Orrin Hatch, R-Utah, expressing his fear over a possible U.S. invasion of Iran.

Hezbollah has denied any activities in Iraq, saying it operates only in Lebanon.

Bergner said a senior Lebanese Hezbollah operative, Ali Mussa Dakdouk, was captured March 20 in southern Iraq. Dakdouk, a 24-year veteran of Hezbollah, was sent to Lebanon "as a surrogate for the Iranian Quds Force" to finance and arm militant cells to carry out attacks on U.S. and Iraqi troops, he said.

The goal was to organize militants "in ways that mirrored how Hezbollah was organized in Lebanon," Bergner said. Hezbollah is one of the region's most disciplined and sophisticated militant groups, able to fight Israel's military to a near standstill in a war last summer.