U.S. Ambassador to Iraq Ryan Crocker on Monday urged Iran to stop supporting Iraq's militias in a rare but "positive" meeting with his Iranian counterpart in the capital.

Crocker said in a news conference that his talks with Iranian ambassador to Iraq Hassan Kazemi Qomi were "positive" and "business-like" and both parties agreed for a stable Iraq.

"The talks proceeded positively and what we need to see is Iranian action on the ground," Crocker said, adding that "I would characterize the atmosphere of the talks as business-like."

Crocker said the four-hour meeting only focused on Iraq and his country insisted that Iran must back a positive course and cut its alleged support for militias in Iraq.

He said he told the Iranians that they back "militia fighting both Iraqi and coalition forces, the fact that a lot of the explosives and ammunition used by these groups are coming from Iran into Iraq."

The U.S. army has frequently accused Iran of arming and training Shiite militia in Iraq, including providing materials of sophisticated armored-piercing bombs. Iran has denied the claims.

Crocker disclosed that the Iranians said they would be proposing a second session and his country would consider when to receive it.