CAIRO, Egypt (AP) _ Top U.S. officials have made strong charges in recent weeks that Iran is directly stirring up trouble in Iraq. But inside Iraq, it's hard to see any change and some American officials in Baghdad say privately the evidence is not that clear.
Most experts on Iran say there is no question that Iran is funneling support to certain Shiite political parties in Iraq, groups it long supported when they were fighting Saddam Hussein.
Ironically, most of that aid appears to go to the same Shiite parties in Iraq that the American government supports and that are part of the government. The more militant Shiite groups are equally critical of U.S. and Iranian influence in the country.
Nevertheless, the anti-Iran rhetoric from Washington has escalated sharply.
Brig. Gen. Michael Barbero, the deputy director of operations for the Joint Chiefs of Staff, told Pentagon reporters on Aug. 23 that there was ``irrefutable'' evidence that Iran was training, funding and equipping Shiite militants in Iraq.
Barbero spoke of a ``policy of the central government in Iran'' to destabilize Iraq and increase the violence there. In the past, U.S. and British officials have alluded to Iranian support for armed groups but always refrained from accusing the Tehran government directly.
The only specifics Barbero cited were allegations _ made before _ that the Iranians were providing insurgents with technology to build more powerful roadside bombs, including armor-piercing ``shaped charges'' developed by Iranian-backed Hezbollah guerrillas in south Lebanon.
In background briefings, however, senior U.S. officials in Baghdad have been far less certain about the nature of Iranian involvement. They say that technology to build ``shaped charges'' in roadside bombs is now widely available across the Middle East.
U.S. officials offered similar skeptical comments last October, when British Prime Minister Tony Blair warned Iran not to meddle in Iraq. Blair cited evidence that explosive devices which killed British troops were similar to those used by Hezbollah.
Unlike their counterparts in Washington, the officials in Baghdad spoke on condition of anonymity because they were not authorized to speak to the media.
Last May, the No. 2 general in Iraq, Lt. Gen. Peter Chiarelli, did say border patrols had found bomb-making materials being smuggled into Iraq from Iran. But he noted that weapons and fighters had been intercepted coming in over Iraq's other borders too, from Jordan, Syria and Saudi Arabia
Earlier in August, U.S. Ambassador Zalmay Khalilzad said in an interview that Tehran was encouraging Shiite militias to step up attacks on U.S. forces in retaliation for the Israeli war with Shiite Hezbollah guerrillas in Lebanon. Iran backs and trains Hezbollah.
Khalilzad blamed the Iranians specifically for an uptick in mortar and rocket attacks on the U.S.-controlled Green Zone in Baghdad, including one attack that wounded four Australian soldiers. Those attacks were believed carried out by the Mahdi Army of radical Shiite cleric Muqtada al-Sadr.
The attacks on the Green Zone from al-Sadr's movement came just after an increase in U.S. and British military pressure on al-Sadr. That included raids on his Baghdad stronghold of Sadr City and the arrest of his top lieutenant in Basra.
Those incidents, rather than any encouragement from Tehran, may well have been behind the Green Zone attacks.
Al-Sadr did sponsor a huge pro-Hezbollah rally in Sadr City on Aug. 4. But aides suggested the rally was aimed more at demonstrating the young cleric's power in Iraqi politics than in mustering support for Hezbollah.
Despite the lack of public evidence, few doubt that Iran is seeking to spread its influence in Iraq, where its fellow Shiites dominate politically.
But many experts on the region believe Iran thinks its interests would be better served by a stable Iraq dominated by Shiites friendly to Tehran. Those experts question why Iran would be trying to stabilize a government already dominated by parties with longtime ties to Tehran.
``Iran has every reason to want a stable Iraq,'' said Juan Cole, a professor of Middle Eastern history at the University of Michigan. ``The evidence is that the Shiite groups most opposed to the (U.S.-led) coalition presence and the current pro-U.S. government ... are also the most anti-Iranian.''
Iran is believed to finance some major Shiite political parties, but mostly ones the United States also backs.
The Shiite party with the closest ties to Iran is the Supreme Council for the Islamic Revolution in Iraq, or SCIRI, which was based in Tehran during the Iran-Iraq war. Its Badr Brigade militia was trained and equipped by the Iranian Revolutionary Guards.
But the United States draws less attention to SCIRI's connection to Iran _ presumably because party members hold key positions in the U.S.-backed unity government in Iraq.
Both Prime Minister Nouri al-Maliki and his predecessor, Ibrahim al-Jaafari, belong to the Dawa party, whose ties to Iran are nearly as strong as SCIRI's.
But al-Sadr is an easier target because of his anti-U.S. stand. He also is believed to receive some Iranian money, but not as much as SCIRI.
Al-Sadr's politics also are more strongly nationalistic, and thus he opposes SCIRI's dream of creating a Shiite self-rule region in Iraq's south _ something Iran presumably would support.
Two other Shiite groups that are close to al-Sadr's movement are outspokenly critical of Iran and its links to SCIRI and Dawa, America's partners in the Iraqi government.
Of course, nothing is certain in the shadowy world of Iranian influence.
In recent weeks, Shiite residents of Sadr City have talked of the Mahdi Army stocking new weapons, perhaps in preparation for a showdown with the U.S. military.
Some of those weapons may have come from Iran, the residents say.