Iraqi Foreign Minister Ibrahim al-Jaafari met President Bashar al-Assad on Tuesday in the first visit by a senior Baghdad official since Syria's conflict began in 2011.
Speaking after meeting Assad and his Syrian counterpart Walid Muallem, Jaafari urged regional support for Damascus as it battles "terrorism".
"Arab countries should support Syria in its fight against terrorism," Jaafari said, calling on "neighbouring countries to stand with Iraq and Syria".
He said extremism "would reach all the countries if there is no cooperation".
Jaafari expressed the hope that his visit would "increase the level of cooperation between Syria and Iraq to counter the dangers threatening our brotherly nations".
In June 2014, Damascus announced its readiness to coordinate with Baghdad in order to face the threat posed by the Islamic State group, which has a strong presence in both countries.
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Muallem emphasised the joint threat, saying that both countries were "in the same trench (fighting) against terrorism".
"We have great confidence... in the Iraqi leaders who will not spare any effort to support Syria and break the embargo imposed on it," Muallem said.
The Syrian minister also called for increased cooperation with Egypt, saying: "Syria, Egypt, and Iraq can change the way events are unfolding in the region."
In September, Iraqi Prime Minister Haider al-Abadi dispatched national security adviser Faleh Fayyad as an envoy to meet Assad.
Fayyad's visit came shortly after a US-led coalition began its air strikes against IS, which controls large swathes of territory in Syria and Iraq.
Shiite militias are supporting both Iraqi forces and Syrian regime troops in attempts to retake territory from IS.
While the Syrian regime's diplomatic links have deteriorated worldwide, particularly with Gulf states, Damascus has maintained ties with Baghdad.