Updated

Iran and Iraq have agreed to work together in tracing thousands of people still missing after the war between the countries in the 1980s, the International Committee of the Red Cross said Thursday.

The neighboring Middle Eastern countries have established how they will gather and share information about the missing and hand over any remains uncovered, the Red Cross said.

The agreement — signed Thursday by representatives from Iran, Iraq and the Red Cross at the neutral organization's headquarters in Geneva — represents "an important step toward easing the heavy burden of thousands of bereaved Iraqi and Iranian families," said Beatrice Megevand-Roggo, the ICRC's head of operations for the Middle East and North Africa.

It was the first time Iran and Iraq signed a direct agreement to tackle the problem together. Previously they each dealt separately with the Red Cross, ICRC spokeswoman Dorothea Krimitsas said. Iranian and Iraqi officials in Geneva did not immediately return calls.

The ruinous eight-year war killed and wounded a total of 1 million people from both sides and remains a thorny subject among many Iraqis today.

Relations between Iraq and Iran have dramatically improved after Saddam's 2003 ouster, which led to the empowerment of Iraq's majority Shiites after decades of oppression at the hands of the Sunni Arab minority, to which the late Saddam belonged.

A large segment of Iraq's ruling Shiite elite lived in exile for years in Shiite, non-Arab Iran before returning home in the wake of Saddam's ouster. Many of them continue to maintain ties with Iran, which the U.S. accuses of arming and supporting Shiite militants in Iraq.

Iran denies this and says that, like Washington, it too wants to see a peaceful Iraq.

There is no generally accepted figure on the number of people missing — many of them civilians. Others included soldiers who went missing in action and people once held as prisoners of war.

"We don't have any comprehensive records," Krimitsas said, but added that the number reached "at least tens of thousands on both sides."

Iran's official reports suggest at least 8,000 Iranians were unaccounted for.

Mass graves from the war are still found Iraq, many holding the bodies of Iranian prisoners.

During the conflict, Red Cross workers visited and registered nearly 40,000 Iranian prisoners of war and more than 67,000 from Iraq.

The Red Cross has since helped in returning many of those prisoners to their homes and in tracing the missing, Krimitsas said

But many families are still searching records at hospitals, police stations, morgues, forensic institutes and aid organizations for information about relatives unaccounted for. The effort is particularly risky for Iranians seeking information in Iraq, which is embroiled in war, the ICRC said.

The Red Cross spokeswoman said the priority would be to speed up the countries' exchange of information. Experts from different government offices would also check their data against one another's and against data collected by the Red Cross.

"We hope that this is going to speed up the process," Krimitsas said.