Over 100,000 Revolutionary Guards and Basij volunteer forces charged towards the Iraqi lines. The Iraqi troops had entrenched themselves in formidable defences, and had set up a network of bunkers, artillery positions and rows of tanks in hull-down position. Iraqi morale had gone up, as they were fighting to defend their own nation. Saddam had also more than doubled the size of the Iraqi army, from 200,000 soldiers (12 divisions and 3 independent brigades) to 500,000 (23 divisions and nine brigades).Among the regular Iranian formations that were charging were the 16th (M60A1 MBTs), 88th (M47 and M48A5 MBTs), and 92nd (Chieftain Mk 3/5 MBTs) Armoured Divisions, along with the 21st, 40th and 77th Mechanized Divisions. Iran's Revolutionary Guards also used the T-55 tanks they had captured in earlier battles.Basiji child-soldiers were sent forth to bodily clear the Iraqi minefields and allow the Revolutionary Guards to advance. The Basij also launched human wave attacks on Iraqi positions, inspired before battle by tales of Ashura, the Battle of Karbala, and the glory of martyrdom. Sometimes an actor (usually an older soldier) would play the part of Imam Hossein and, on a white horse, gallop along the lines, providing the inexperienced soldiers a vision of "the hero who would lead them into their fateful battle before they met their God". The "martyrs" had signed "Passports to Paradise" (as admission forms to the Basij were nicknamed), received a week of basic military training by the Revolutionary Guard, and were sent directly to the front lines. The human wave assaults, often with no support from other military branches due to rivalry with the remnants of the former Imperial Iranian Army, were met with crushing artillery, rocket, and tank fire from Iraq's defence that caused massive losses to the Iranian side.By 16 July the Iranians had in their first attack succeeded in overrunning the forward Iraqi defence lines right at the border, gained in their deepest penetration 16 km (9.9 mi) inside Iraq and claimed to have captured 288 square kilometers (180 square miles) of Iraqi territory albeit with a great deal of casualties. The Iranian forces had penetrated as far as the Kutayba river, a tributary to the Shatt Al Arab river, but failed to cross it. However, the Iranian forces came to a halt as the Iraqis stopped the main Iranian attack and launched frontal and flanking counter-attacks supported by air strikes from fighter-bombers that pushed the Iranians back to within 4 kilometers (2,5 miles) from the border.The Iraqis used their Mi-25 helicopters, along with Gazelle helicopters armed with HOT missiles against columns of Iranian mechanised infantry and tanks. These "hunter-killer" teams of helicopters, which had been formed with the help of East German advisors, proved to be very costly for Iranians. Aerial dogfights occurred between Iraqi MiG's and Iranian Phantom's. During this battle, the Iraqis also made first significant use of chemical weapons, contributing to their successes on the battlefield.[63] During this instance, the Iraqis used large amounts of non-lethal tear gas to disrupt the offensive, throwing an entire attacking Iranian division into chaos.On 21 July, the Iranians tried again with a second thrust and managed to penetrate through the Iraqi defence lines once again. However, only 13 km (8.1 mi) from Basra, the poorly equipped Iranian forces were surrounded on three sides and cut-off from Iranian logistics and supply units by Iraqis who counter-attacked with heavy weaponry. The Iraqi counter-attacks once again pushed the Iranians back to their starting point where fighting slowed to a stalemate. Only a last-minute attack by Iranian Cobra helicopters stopped the Iraqis from routing the Iranians completely. Three more similar Iranian attacks occurred around the Khorramshar-Baghdad road area towards the end of the month, but none were significantly successful.The final Iranian thrust came on 1 August, when in a la

Question: Who helped Iraqis use mi-25 and gazelle helicopters against the Iranian military?
Answer: East German advisors