Aljazeera:

During the three-day visit, agreements will be signed in fields such as energy, transport, agriculture and more.

Iran's President Hassan Rouhani has arrived in Baghdad on his first official visit to the nation that Tehran once fought a bloody war against and later backed in the battle with the Islamic State of Iraq and the Levant (ISIL or ISIS) group.

Rouhani was welcomed by Iraqi Foreign Minister Mohamed Ali Hakim on Monday.

He will visit a Shia shrine in the Iraqi capital and then meet President Barham Salih and Prime Minister Abdel Abdul Mehdi, as well as visit other politicians and Shia leaders.

Since Rouhani's election in 2013, Iraq has relied on Iranian paramilitary support to fight ISIL following the group's capture of the Iraqi city of Mosul and other territories in both Iraq and Syria.

Rouhani's visit is a strong message to the US and its regional allies that Iran still dominates Baghdad, a key arena for rising tension between Washington and Tehran.

"We are very much interested to expand our ties with Iraq, particularly our transport cooperation," Rouhani said at Tehran's Mehrabad airport before departing for Iraq.

"We have important projects that will be discussed during this visit."

Speaking from the Iraqi capital Baghdad, Al Jazeera's Natasha Ghoneim said Rouhani's visit is a two-pronged message to both the US and inner Iranian dissent.

"Since the US reimposed sanctions last year the economy has continued to deteriorate, and [Rouhani] is facing pressure from within," she said.

"There have even been calls for his ouster. So he comes to Iraq with the hope of bolstering economic ties in Iraq and Iran and with the hope of sending a clear message to the US that this relationship between the two countries is unshakeable."

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