U.S. officials next week will unveil evidence that supports its case on Iranian interference in Iraq, news that came on a day that Bush administration officials were defending themselves against news reports of policy shifts that allow attacks on Iranians in Iraq.

State and Defense department officials said that the "dossier" on Iranian activities will be released sometime next week in one of the regular military briefings from Iraq.

State Department spokesman Sean McCormack described the the information as a "mountain of evidence." U.S. Ambassador to Iraq Zalmay Khalilzad has driven efforts to prove Iran's actions.

U.S. forces are still holding five Iranians arrested earlier this month in Irbil. Military officials say the Iranians were not diplomats as Tehran claims, but part of a network working against U.S. troops.

On Friday the Washington Post reported that administration officials recently have authorized U.S. military to kill or capture Iranian operatives caught inside Iraq, although administration officials said Friday that this is not new information, and that U.S. forces have always had that authority.

President Bush defended the policy on Friday.

"It makes sense that if somebody's trying to harm our troops, or stop us from achieving our goal, or killing innocent citizens in Iraq, that we will stop them," Bush said after a White House meeting with military officials. "It's an obligation we all have ... to protect our folks and achieve our goal."

Officials did say, however, that they will be taking a tougher stance against Iran.

One military official told FOX News there was an increase in intelligence over the past few months indicating Iran was providing material support and training on how to make improvised explosive devices, or IEDs. Sources said that information has coincided with an increase in the number of Iranians inside Iraq. Bush's national security team concluded the matter had to be dealt with.

Officials said there was no presidential order or "finding;" there was no specific authorization that changed the rules of engagement, although a decision was made to adopt the tougher stance.

The aggressive new policy came in response to intelligence that Iran is supporting terrorists inside Iraq and is providing bombs -- known as improvised explosive devices -- and other equipment to anti-U.S. insurgents.

"The president and his national security team over the last several months have continued to receive information that Iranians were supplying IED equipment and or training that was being used to harm American soldiers," National Security Council spokesman Gordon Johndroe said.

"As a result American forces, when they receive actionable information, may take the steps necessary to protect themselves as well as the population," Johndroe said.

While promising tougher action, the White House said the United States does not intend to cross the Iraq-Iran border to attack Iranians.

Five Iranians were detained by U.S.-led forces earlier this month after a raid on an Iranian government liaison office in northern Iraq. The move further frayed relations between the two countries, already tense because of U.S.-led efforts to force Tehran to abandon its suspected nuclear weapons program.

"We believe that we can solve our problem with Iran diplomatically and are working to do that," Bush said. "As a matter of fact, we're making pretty good progress on that front."

The administration said at the time that U.S. forces entered an Iranian building in Kurdish-controlled Irbil because information linked it to Revolutionary Guards and other Iranian elements engaging in violent activities in Iraq.

But Iraqi Foreign Minister Hoshyar Zebari, a Kurd, contended the Iranians were working in a liaison office that had government approval and that the office was in the process of being approved as a consulate. In Iran, Foreign Minister Manouchehr Mottaki said the U.S. raid constituted an intervention in Iranian-Iraqi affairs.

FOX News' Nina Donaghy, Wendell Goler, Mike Emanuel and Nick Simeone and The Associated Press contributed to this report.