U.S. forces in Iraq have captured a small number of extremists who have been trained recently in Iran in mortar and rocket operations, according to a top U.S. commander.

"I have seen ... a steady increase in support to Shiite extremists," said Lt. Gen. Ray Odierno, the commander of Multinational Corps Iraq. "I think they are trying to surge their support to Shiite extremists. We've seen an increased flow of training to mortar teams and rocket teams, we've seen an increase in some flow of weapons and munitions into Iraq. We are working very hard to cut those lines every day from Iran."

Odierno said a small number of Shiite Iraqi mortar and rocket teams trained in Iran have been captured inside Baghdad. They have targeted not just U.S. and Iraqi forces but also government of Iraq targets inside the protected Green Zone.

He fingered Iran's Revolutionary Guard as well as other Iraqi groups with long established ties to Iran.

"It's probably in some cases a network that was developed prior to Saddam Hussein's downfall and they continue to operate," he said.

Anti-Saddam Iraqi Shiites have long moved in and out of Iran and received training and aid there in a more than three decades-long, low-grade Iranian-aided campaign against the regime. Two of Iraq's most powerful political parties, al Dawa and the Supreme Islamic Iraqi Council (formerly SCIRI), have close ties to Iran, a Shiite theocracy.