The fire inside reactor No. 4 continued to burn until 10 May 1986; it is possible that well over half of the graphite burned out. The fires were extinguished but many firefighters received high doses of radiation.
On 15–19 May, Iraqi Army's Second Corps, supported by helicopter gunships, attacked and captured the city of Mehran. Saddam then offered the Iranians to exchange Mehran for al-Faw. The Iranians rejected the offer. Iraq then continued the attack, attempting to push deeper into Iran. However, Iraq's attack was quickly warded off by Iranian AH-1 Cobra helicopters with TOW missiles, which destroyed numerous Iraqi tanks and vehicles.