Iranian President Mahmoud Ahmadinejad said in Iraq on Thursday that Tehran and Baghdad have an "exceptional" role to play in the region's security.

"The role of the two countries in the security of the region is exceptional," Ahmadinejad told reporters in Baghdad's heavily fortified Green Zone, but without elaborating.

"We carry a joint message, which is a message of progress and stability and security, and also a message of peace," Ahmadinejad said after talks with Iraqi Vice President Khudayr al-Khuzaie.

Ahmadinejad, whose term ends early next month, arrived in Iraq to a red carpet welcome.

He also met Prime Minister Nuri al-Maliki, a statement on the premier's website said.

Maliki said at the meeting that "Iraq supports peaceful solutions for all the problems in the region," and told Ahmadinejad Iranian companies were welcome to take part in the reconstruction of Iraq, the statement said.

Ahmadinejad plans to visit the shrine of Imam Hussein in Karbala and that of Imam Ali in Najaf, two of the holiest sites in Shiite Islam, Maliki's spokesman Ali Mussawi said.

Iraq and Iran fought a bloody 1980-88 war launched by now-executed dictator Saddam Hussein.

But the neighbours have drawn closer since Saddam's overthrow by US-led forces in 2003, which ultimately paved the way for expanded Iranian influence in Iraq.

The United States has repeatedly said that Iran is using Iraqi airspace to supply arms to Syrian President Bashar al-Assad's regime, which is locked in a brutal civil war with rebels seeking his overthrow.

Iran has stood by its ally Assad in the more than two-year conflict, while Iraq has sought to publicly avoid backing either side.

Iran has also supplied weapons and training to Lebanese Shiite militant group Hezbollah, which has entered the war on Assad's behalf.