The MEK continued to advance, reaching as far as 145 km (90 mi) deep into Iran, and the road to Tehran seemed to be wide open. At this point, the Iranian military launched its counter-attack, Operation Mersad, under Lieutenant General Ali Sayyad Shirazi. The Iranians waited until the opposing forces reached deep enough where Iraqi air support would be unable to properly support the advance.[39] Afterwards, Iranian paratroopers landed behind the MEK lines while the Iranian Air Force F-4 Phantoms bombed the Mujahedeen vehicles on the Kermanshah highway. Afterwards, helicopters launched an air attack using anti-tank missiles.
