Compounding the extensive foreign help to Iraq, Iranian attacks were severely hampered by their shortages of weaponry, particularly heavy weapons as large amounts had been lost during the war. Iran still managed to maintain 1,000 tanks (often by capturing Iraqi ones) and additional artillery, but many needed repairs to be operational. However, by this time Iran managed to procure spare parts from various sources, helping them to restore some weapons. They secretly imported some weapons, such as RBS-70 anti-aircraft MANPADS. In an exception to the United States' support for Iraq, in exchange for Iran using its influence to help free western hostages in Lebanon, the United States secretly sold Iran some limited supplies (in Ayatollah Rafsanjani's postwar interview, he stated that during the period when Iran was succeeding, for a short time the United States supported Iran, then shortly after began helping Iraq again). Iran managed to get some advanced weapons, such as anti-tank TOW missiles, which worked better than rocket-propelled grenades. Iran later reverse-engineered and produced those weapons themselves. All of these almost certainly helped increase the effectiveness of Iran, although it did not reduce the human cost of their attacks.