[d] Iraq had originally only intended to retake the al-Faw peninsula it had lost to Iran, but following the battles' extraordinary success due to the complete collapse of the Iranian troops present, the Iraqi command decided to expand the battle into a larger offensive campaign, ultimately leading to the expulsion of all Iranian forces present within Iraq and subsequent renewed invasion of Iran.

Following the Iranian Karbala campaigns of 1987, but before the end of summer, the Iraqi Army started secretly practicing maneuvers in the desert behind Basra.

The training maneuvers involved multiple Army and Republican Guards divisions and huge mock-ups of objectives Iraq intended to seize back from Iran.

[16] In addition, Iran began to focus on creating an insurgency inside of Iraq, similar to the Viet Cong during the Vietnam War.

The taking of the peninsula by the Iranians was a strong blow to Iraq's prestige whilst also threatening Basra from the south-east.

[9] This stunning success led the Iraqi command to expand the original battle into a larger offensive campaign against Iran.

Using artillery, they would saturate the Iranian front line with rapidly dispersing nerve gas, while longer-lasting mustard gas was launched via fighter-bombers and rockets against the Iranian rear, creating a "chemical wall" that blocked reinforcement At 9:30am on 25 May 1988, Iraq launched what became known as Tawakalna 1,[18] consisting of one of the largest artillery barrages in history, coupled with chemical weapons.

The Iraqi forces deployed consisted of possibly up to 135,000 men composed of various elements of the Republican Guard and 3rd Corps, attacking along a 15-mile front.

[12] Faced with such losses, Khomeini appointed the cleric Hashemi Rafsanjani as the Supreme Commander of the Armed Forces, though he had in actuality occupied that position for months.

The Iranians, counter-attacked with a force of 20,000–25,000 Revolutionary Guards in formations of as many as 50 battalions, and managed to strike Saddam's presidential palace in Baghdad using fighter aircraft.

[12] After 3 days of fierce fighting which decimated the Revolutionary Guards force, the Iranians were driven back as the Iraqis launched 650 helicopter and 300 aircraft ground-attack sorties.

The attack began with one of the largest artillery barrages in history, coupled with massive amounts of poison gas, incapacitating many of the defenders.

[18] On July 12, Iraqi forces shelled the Iranian positions around the Zubaidat area near the border, a group of oil fields east of Amarah.

[13] By 12 July at the central front, the Iraqis had driven away from Amarah,[12] and moved into Iran on a broad offensive, swept aside scattered Iranian resistance, and captured the city of Dehloran and Qasre Shirin, 30 kilometres (19 mi) and 20 kilometres (12 mi) respectively inside Iran, and captured another 2,500 Iranian troops along with substantial amount of armour and materiel,[12] which took days to transport to Iraq.

In addition the Iraqis captured the Iranian small towns of Sumar, Naft Shahr, Sarpol Zahab, Saleh Abad, Mousiyan, Patak, as well as dozens of other villages along the central and southern portions of the border, along with occupying and cutting off the strategically important Ahvaz-Khorramshahr highway and in places reaching and occupying important crossing-points on the Karkheh river.

However, soon after Khomeini's acceptance of the UN ceasefire deal on 20 July 1988, the Iraqis withdrew from the towns, claiming that they had no desire to conquer Iranian territory.

The Iranian troops in the various sectors involved in the operation had received a fatal blow; their various headquarters and formations had virtually ceased to exist.

[19] After a series of battles, in which Iraq had emerged as the victor, the leadership in Baghdad stated that they did not desire to conquer Iranian territory.

The success of the Iraqi armed forces had convinced the clerics of Iran that they could not attain their objectives on the field of battle and to accept the ceasefire.