Iraq announced it was restoring full diplomatic relations with Syria after a 26-year break on Tuesday and hailed a pledge from its western neighbour to do more to cooperate on security.
"We have signed a little while ago an agreement to restore complete diplomatic relations with Syria," Foreign Minister Hoshyar Zebari told a joint news conference with his visiting Syrian counterpart Walid Muallem.
"(The) Iraqi flag will be raised in Syria and the Syrian flag will be hoisted in Baghdad," Zebari said.
The Iraqi minister said agreement had also been reached on closer security co-operation following repeated US accusations that Syria was turning a blind eye to Arab insurgents smuggling men and materiel across the border.
"There was an agreement to have meetings between security officials from both countries and we also discussed developing commercial relations," he said.
The Syrian minister acknowledged that his talks in Baghdad had been "frank after they (relations) were disturbed all these years."
Saddam Hussein's regime cut ties with Syria in 1980 in protest at its support for Iran after an eight-year war between the two neighbours broke out that year.
Muallem said he hoped the restoration of normal relations would put an end to US criticism of Syria over its role in Iraq.
"I do not want to go back to the former accusations. We seek future co-operation in all fields," said the minister, the first Syrian official to visit Iraq since the US-led invasion of 2003.
The White House swiftly called on Syria to show it was genuinely committed to "constructive engagement" through action on the ground to stop the flow of foreign fighters into Iraq.
"We've always encouraged Iraq's neighbours to take a role in supporting and assisting the unity government in Iraq," Gordon Johndroe, spokesman for the White House's national security council, told AFP.
"Syria needs to now demonstrate that it is committed to constructive engagement and fostering an Iraq that can govern, sustain and defend itself," Johndroe said.
"One of the first steps Syria could take is to strengthen its border with Iraq and stop the flow of foreign fighters into that country."
The rapprochement between the two neighbours comes amid mounting calls for the US administration to engage Syria and its regional ally Iran in efforts to stabilise Iraq three and a half years after the invasion.
British Prime Minister Tony Blair has urged President George W. Bush to rethink US coldshouldering of the two governments and engagement is expected to be among the key options to be proposed by the Iraq Study Group, a US bipartisan panel that is to present its findings early next month.
Iraqi President Jalal Talabani is to travel to Iran Saturday for talks with his counterpart Mahmoud Ahmadinejad and a spokesman for the Iranian president said efforts had been to get Syrian President Bashar al-Assad to join the meeting "to try to resolve the existing misunderstandings".
But Zebari denied that there were plans for a three-way summit in Tehran, saying that instead Talabani had been invited to Damascus.
"We contacted the office of the president to check about the summit. There is no summit between Iraq, Syria and Iran," he said.
"The president has an invitation to meet and hold (an) Iraqi-Iranian summit."
But Zebari said that the Iraqi government's overtures to two countries long coldshouldered by the United States should convince any remaining doubters of its independence.
"This visit has opened the way for us and has sent positive messages to the international, regional and Arab countries that we are the masters of our decisions and national interests," he said.
Analysts said the rapprochement between Iraq and Syria was likely to add grist to the mill of those pushing for the US administration to engage.
There were elements of Muallem's visit "that will both energise and give more weight to the review here and the argument to engage the Syrians," said Scott Lasensky of the US Institute for Peace, a think tank that has been advising the Iraq Study Group.
But Iraqi Prime Minister Nuri al-Maliki made clear that he still expected to see more action from Syria on security, regardless of the state of its relations with the United States.
"If Syria or any other state has differences with the United States, it's their own business," Maliki told a joint news conference with Muallem on Monday.
"It should settle these differences, but not at our cost," he said.