Following the Battle of Western Iraq in spring of 2013, no serious efforts were made between North Syria, Iraq and Iran toward peace negotiations. Iraqi president Fuad Masum made it plain that the use of force is the only thing that would end North Syrian interference to Iraq's political and military wishes, and on September 18 at 11:30 PM Baghdad time, Masum declared an attrition war against North Syrians.
On September 21, Syrian president Bashar al-Assad decided to use this as an opportunity to regain lost territory from the Syrian Civil War, as well the Levantine War and declared war against North Syria, opening up a Syrian Front and an Iraqi Front.
On the Iraqi Front, the North Syrians and Iraqis engaged in artillery duels along the North Syrian-Iraqi border. The war was also characterized by night raids, aerial assaults and sabotage missions. While the North Syrians performed small-scale incursions, the Iraqis prepared for bigger battles.
On the Syrian Front, the North Syrians and Syrians engaged in mostly armored battles.
In the end, a U.N.-mandated cease fire was signed in Beirut, Lebanon thus ending the war. No border changes were made.
September 18 - In retaliation for what Iraqi president Fuad Masum claimed as an "act of aggression", Iraq declares war on North Syria. As a result, North Syria sends a pre-emptive attack in western Iraq.
September 19 - The war begins, North Syrian assault brigades are routed in western Iraq and replused
September 20 - The North Syrian Royal Air Force bombs Iraqi military installations in southwestern Iraq near Syria's borders
September 21 - Iraq and North Syria exchange artillery fire, Iraqi military fires rockets into the North Syrian town of Malikiyah, killing five North Syrian civilians
September 22 - More artillery exchanges, an Iraqi barrage kills 20 North Syrian soldiers, North Syria responds by shelling the western Iraqi city of Sinjar with rockets
September 23 - The Syrian Arab Republic declares war against North Syria in an attempt to re-take the northern Levant, joining Iraq. North Syrian airborne Special Forces carry out Operation Karim, destroying communications between Iraqi and Syrian militaries, another raid is conducted in the Iraqi city of Al-Qa'im resulting in the death of 98 Iraqi soldiers and another 130 injured
September 24 - North Syrian Royal armored brigades bombard the Syrian city of Tadmur, they are met with resistance from T-72 Soviet-style Syrian tanks
September 25 - North Syrian sabotage units raid an Iraqi military prison base in Tal Afar, Iraqi soldiers sustain heavy damage, North Syria begins to install bases in western Iraq, the Iraqis respond by shelling North Syrian military installations damaging some North Syrian vehicles and armor, a meeting in the United Nations is done for cease-fire talks in Beirut, Lebanon
September 26 - Iraqi Air Force attacks eastern North Syria, four Iraqi warplanes are shot down by North Syrian anti-aircraft, North Syrian armored units destroy Syrian anti-air craft classes and push deep into Syrian territory
September 27 - Operation Sadir, North Syrian tactical and Special Units paratroopers attack Rutba, killing 90 Iraqi soldiers and injuring 100 at the loss of ten killed and four injured, they dismantle a Russian-supplied radar, Syrian army manages to push North Syrians 45 miles up north
September 28 - Iraq, North Syria and Syria agree to the ceasefire and withdraw forces from one another's countries