战役背景：
Iran launched three diversionary attacks prior to Operation Nasr. The first one began on January 4–6, near Qasr-e-Shirin in central Iran. A brigade of regular Iranian mountain troops attacked Iraqi forces that were in a defensive position, blocking the main highway between Tehran and Baghdad. In a pattern which would become all too familiar later during the war, the Iranians infiltrated through the Iraqi positions, and even captured some enemy units. But the battle broke down into a fight for each hill and mountain peak, and the Iraqis rushed reinforcements. While Iran gained 8 kilometers, they did not achieve any significant tactical advantage.
The second attack involved other Iranian mountain troops infiltrated and attempted to liberate Mehran. The end result was similar to the previous battle.
The third attack was more serious. It involved an Iranian mechanized division attacking Iraqi forces west of the Karun River in the vicinity of Ahvaz. The goal of the battle was to drive the Iraqis out of artillery range of the city. The terrain was more suitable for vehicles (although it did not favor Iran), and the road network was good. They achieved surprise, and drove the Iraqis back several miles, however Iraq remained within artillery range of the city and the Iranians took moderate to heavy losses.
he Iranian forces began to move down the paved road which ran between Susangerd and Dezful. They moved very slowly, and each column moved separately. Unknown to the Iranians, their plans had already begun to go awry when Iraqi observation aircraft spotted the column moving south towards Abadan. Thus their plans for surprise had been foiled. The Iraqis immediately began planning their action. Iraq moved their 10th Armored Brigade, and positioned them on the Iranian line of advance on the road. The Iraqis dug their tanks into a hull-down position, meaning they were dug into the mud of the marshes and used as static pieces. While the Iraqis often lacked the skill to maneuver, and regularly put their tanks in dug-in positions gaining the advantage of a smaller/lower silhouette, in this instance it would prove to be successful, because the mud of the marshes would hamper armored maneuver. The Iraqi tanks (Soviet T-62 and T-55) were dug into positions both in front of and on the side of the Iranian line of advance. The Iraqis were also supported by attack helicopters such as Mi-8s, BO-105s, Alouette IIIs, and Sa-341/342 Gazelles. Thus the Iraqi trap was set.
On 6 January, the next day, Iranian forces came into contact with the Iraqi armor. Iran*s shortage of reconnaissance proved to be disastrous as they failed to see the approaching trap. The Iraqis began firing at the Iranian tanks from the front and both sides. The Iranians tried to drive through the Iraqi forces in an armored spearhead, but took heavy losses. They then tried to maneuver. But that involved driving their tanks off the paved road, and into the mud. Iranian tanks then got stuck in the mud. The first Iranian brigade was decimated, and many tanks were destroyed or abandoned in the mud. Nevertheless, the Iranians refused to abort the attack, and their next brigade moved into action.
The second Iranian brigade advanced, and the results were similar. Iranian helicopters (AH-1J SeaCobras) also joined the battle, destroyed several dug-in Iraqi tanks, but their efforts were not enough to alleviate the pressure on the Iranian ground force and the Iranian armor kept taking heavy losses. The Iraqis also had anti-aircraft weapons, and several Iranian helicopters were shot down. To make matters worse, Iraqi mechanized infantry with anti-tank weapons joined in, turning the battle into a slaughter for the Iranians. Fighting took place at close range and was brutal. Nevertheless, the Iraqis also took many losses, because their tanks were in static positions and because of superior armor and firepower of the Chieftain tanks as well as the advantage of better aiming optics on the Western made tanks (M60A1 & Chieftain MK 3/5) and TOW-armed AH-1J Seacobras which also provided superior firepower and better aiming optics compared to Iraq*s soviet-manufactured T-55s & T-62s and Soviet/French-manufactured helicopters. Just when things were going badly, Iraqi aircraft also bombed the pontoon bridge across the Kharkeh River, trapping the Iranian tanks and preventing their retreat. Iran*s infantry was also stuck on the opposite bank (they hadn*t moved into action yet) and separated from joining the battle. Iranian helicopters attempted to fight back, but they were attacked by Iraqi fighter jets, which destroyed or damaged several helicopters.
By 8 January, the entire Iranian attack was in chaos. Many tanks from the first two brigades had been lost, either destroyed, or stuck in the mud and abandoned. The third Iranian brigade attempted to continue the attack, but could make little headway. Instead, Operation Nasr was aborted, and the Iranians moved to retreat. The infantry force (which never had a chance to join the battle) instead moved into a defensive position to prevent an Iraqi counterattack. Iranian engineers at the last second managed to rebuild the pontoon bridges over the Kharkeh river, and the third Iranian tank brigade managed to break away from the combat and retreat from the Iraqi forces and move back across the Kharkeh River.
Meanwhile, during the débâcle at Dezful, Iranian infantry forces at besieged Abadan attempted their breakout, in order to link up with the armored column. Even if the 16th armored division had not been defeated in battle, it was unlikely that they would have been able to reach them. The Iranian infantry took heavy losses and were forced to retreat back to Abadan.
The Iraqis had heavily defeated the Iranians. While the Iranians had been a powerful force prior to the revolution, the damage inflicted by the revolution had made it possible for the Iraqis to gain a victory like this. Nevertheless, poor Iraqi training saved the Iranians from a total rout. The Iraqis primarily dug in their tanks into the ground to act as static artillery, and while that worked at the fighting around Dezful and Susangerd, it meant that they were unable to follow up their victory and destroy the Iranians. Instead, they remained dug in as the Iranians withdrew. A minor Iraqi counterattack with helicopters and some armor was beaten back by Iranian forces near the town of Shush which lay just behind the Karkheh river on the line of advance to Dezful.
For the Iranian military, this major defeat had serious implications. Iran had lost between 88 and 214 tanks (depending upon the source), at least 100 other armored vehicles, some heavy artillery and a large portion of the 16th armored division. Many armored vehicles had been captured intact as they had been abandoned or stuck in the mud, and were put on display in Iraq (some were later even sold to Jordan, while others remained in storage until the 2003 invasion). The losses would have been much worse had not the Iranians managed to reassemble their pontoon bridge. Prior to the revolution, Iran had had 1,700 tanks (which dwindled to 1,000 usable ones after the revolution). With their defeat at Dezful, at least 10-20% of that entire force was destroyed, a major weakening of Iranian military power. To make matters worse, with US-led sanctions on Iran, those tanks could not be replaced while the Iraqi ones could easily be (since they weren*t under an embargo and had the support of the west).
Despite their decisive victory, close to 45 Iraqi tanks and other armored vehicles were destroyed. Since they fought from static positions, they were easier targets. Nevertheless, their losses could be replaced, while the Iranians* could not.