BAGHDAD -- The U.S. military worried Sunday about "mixed messages" from Iran, listing a dramatic drop in Iranian-made weapons reaching Iraq but no reduction in the training and financing of Shiite militants.

The report card further muddles U.S.-Iranian relations as Washington ratchets up its anti-Tehran rhetoric in the shadow of a recent intelligence report that the Islamic Republic halted a nuclear weapons program four years ago.

Rear Adm. Gregory Smith, a U.S. military spokesman in Baghdad, said attacks using powerful Iranian-made bombs known as explosively formed penetrators, or EFPs, have fallen off in recent days after a sharp but brief increase in the first half of the month.

Late last year, the military said the flow of EFPs into Iraq had slowed, but Gen. David Petraeus, the top U.S. commander, said last week that attacks with the weapons had risen by a factor of two or three in the first half of this month.

Smith said the increase fell off again last week.

"The number of signature weapons that had come from Iran and had been used against coalition and Iraqi forces are down dramatically except for this short uptick in the EFPs in the early part of January," Smith said at a news conference.

Smith said the U.S. is trying to understand the various ways in which Iran exerts influence inside Iraq, including training of and financial support to militias as well as the smuggling of weapons.

"We don't think that the level of training has been reduced at all. We don't believe that the level of financing has been reduced. It's uncertain again what is happening in Iran that's leading to that occurrence."