Citing the "indiscriminate bombardment of Iraqi residential areas by the U.S. occupying forces," Iran has suspended talks with the United States on helping with the security situation in Iraq:

The Americans believe that Iran is supplying weapons and training to Shiite militias in Iraq, but the Iranians have denied that they are interfering here. It remains uncertain whether some of the weapons found in Iraq that appear to be Iranian came directly from Iran or through third parties.

The Iraqis are forming a committee with experts from Interior and Defense Ministries to look into the allegations against Iran.

The State Department did not comment directly on the talks, but a spokesman, Tom Casey, said, "The fact remains, though, that the Iranian government continues, despite their public statements of support for the Iraqi government, to play this negative role, to provide this kind of assistance to militant groups and to militia groups."

"It's something we want to see stopped, and it's something the Iraqis want to see stopped," Mr. Casey said.

Two things are clear. The talks have not borne much fruit, so suspending them is almost cost free, at least in the short term. The downside is that the talks have been a way for the two countries, which do not have diplomatic relations, to have face-to-face conversations. Several Iraqi politicians said they believed that the Iranian suspension was as much in retaliation for the United States' criticism of Iran's nuclear program as it was for Iraq policy.

"Some Iranian officials believe that Iraq is a better location to pressure the Americans over Iran's diplomatic crisis with them," Ali al-Dabbagh, an Iraqi government spokesman, told Al Hurra, a satellite channel, on Monday evening.

In addition, Iran loses nothing in Iraq by denouncing strikes on Shiite civilians, especially since it has also said it approves of the Iraqi government's effort to halt the activities of illegal militias. While those two positions may sound contradictory, they are plausible here. The Iraqi government also says it wants to help civilians and is taking aim only at the militias. The reality is that when forces go after insurgents in urban areas, it is impossible to avoid hitting some innocents as well.