MADRID (AFP) - Spanish police halted the illegal export of nine Bell-112 military transport helicopters to Iran and detained eight people including three Iranians, they said Thursday. Police seized the US-made helicopters and arrested five Spanish businessmen suspected of trying to export them along with three Iranians accused of negotiating the purchase of military materiel. In the operation, dubbed "Nam", they raided industrial warehouses in Madrid and Barcelona and snatched helicopters destined for Iran, police said in a statement. They also seized aviation spare parts allegedly destined for export to Venezuela, police said. Police estimated the total value of the helicopters, spares and other military materiel at about 100 million euros ($140 million). Police said the aircraft were subject to European Union and Spanish controls and were banned for export by the United Nations. Interior Minister Alfredo Perez Rubalcaba said the group bought the helicopters in Israel, Iran's arch-foe. "There was a group of Spanish citizens who bought material, in this case helicopters, in Israel and then tried to sell them to other nations to which you can't export arms, like Iran," he told a news conference. "This is an important operation, which started a while ago," he added. With a top speed of 230 kph (140 mph) and an average range of 600 kilometres (370 miles), the helicopters were designed to ferry troops and military equipment, police said. The Spanish companies flouted export requirements, failing to obtain licences for the export of military materiel or so-called dual-use goods that can have military applications, police said. The firms knew the export of the aircraft and spare parts was banned, they said, accusing them of concealing them in the warehouses, owned by a syndicate of the Spaniards who had been detained. The helicopters and spares were being prepared for assembly and disassembly before export to Iran and Venezuela, police said. "They tried to protect the export sale, which could have resulted in revenue of about 100 million euros, under the cover of legal aviation repairs," the statement said. Police said they found out about the arrival in Spain of the Iranian purchasers who had come to formalize the deal and they then launched an operation to arrest them. They arrested five people in Madrid and three in Barcelona, and raided another three addresses resulting in the seizure of the nine Bell helicopters, aviation materiel and spares and related documents.