Siege of Abadan

The Siege of Abadan was a major action during the early part of the Iran–Iraq War.

Prelude
Abadan island was the site of the Abadan Refinery, one of the worlds largest oil refineries.

The plan
In September 1980 Iraqi President Saddam Hussein launched a surprise attack against Iran and invaded Iranian territory on a broad front. Iraq's initial plan to attack Abadan Island called for an reinforced armored division to cross the Shatt al-Arab near Kharkiya on the road heading from Baghdad to Basra and then head south to capture the cities of Khorramshahr and Abadan, and subsequently engage any remaining local Iranian units. This reinforced division to be used included 500-600 tanks, as well as some special forces units, for a total troop strength of 20,000 men.

Iraqi commandos, driven by Iraqi initial success in the attack on Khorramshahr, had crossed the Karun River and reached the Abadan city limits on 22 September, but had been forced back by stiff resistance from Iranian paramilitary units, causing the Iraqis to withdraw to the north side of the Karun River, at the cost of several tanks and APCs. By 4 October Iraqi commanders reported that they had secured the main road from Abadan to Ahwaz, however it was not until late November that Iraq fully controlled the bridge to Abadan.

As the Iraqi army became preoccupied with the ongoing Battle of Khorramshahr, the original plan was heavily edited, with instead of calling for a quick engagement and occupation of Abadan, the plan now was to isolate local Iranian units within Abadan, and then lay siege to the island.

The battle
On November 3, Iraqi forces reached Abadan in Iran's Khuzestan province. Iranian resistance proved too strong, however, so Iraqi commanders called for reinforcements. A second, weakened armored division with a strength of approximately 4,500 men and 200 tanks was sent to cut off Abadan and surround the city from the northeast, bypassing Khorramshahr, which was still under siege, by crossing the Karun River to the north of the city. These two Iraqi divisions faced an unknown number of Iranian troops. Most likely sources estimate that a single brigade defended Khorramshahr supported by two operational reserves located further north.

The siege
Although the Iraqis were repulsed by the Iranian Pasdaran unit, they managed to surround Abadan on three sides and occupy a portion of the city. However the Iraqis could not overcome the stiff resistance; sections of the city still under Iranian control were resupplied at night by boat. The Iraqis kept up a siege for several months, but never succeeded in capturing Abadan. Much of the city, including the oil refinery, was badly damaged or destroyed by the siege and by bombing.

Iraqi June Offensive
Facing declining morale and with the Shatt-al-Arab waterway still blocked by the besieged Iranians, Saddam ordered the Iraqis to attack in June, 1981. The Iranians had reinforced the garrison with 15,000 troops, including the Pasdaran, regular army, and Khuzestani Arab fighters. Iraq unleashed an offensive against the city, using 60,000 troops and tanks, outnumbering the Iranians 6-1. Despite that, the Iranians defeated the Iraqi assaults. The Iranians used their Chieftain tanks to help defeat the Iraqis.

Breaking of the Siege
see: Operation Samen ol-A'emeh

From 22–27 September 1981, Iran carried out Operation Samen-ol-A'emeh. During this battle, Iran carried out the first major use of human wave attacks. The siege of Abadan was broken, Iran took 3,000 casualties while the Iraqis took half of that number. Iran captured 2,500 prisoners and destroyed armored vehicles, while losing of their own 150 M-60 Patton tanks.

Aftermath
Abadan was largely in ruins in the aftermath of the siege. The Iraqi threat to Abadan had been broken, and the Iranians had managed to launch their first successful offensive against Iraq. Eventually, it would result in the driving out of Iraqi troops from Iran and the Liberation of Khorramshahr in 1982.