"We have 250 planes in the country, 230 need to be replaced", Abezadeh said, pointing out that the transaction still requires the approval of the US Treasury Department. Iran's efforts to upgrade its ageing air fleet may be complicated by regulatory hurdles, with manufacturers required to obtain licenses from the U.S. Treasury Department and some remaining sanctions making it hard to arrange financing.
Boeing confirmed on June 15 that it was in talks with Iranian airlines interested in buying its passenger planes.
Regulatory hurdles and U-S sanctions that remain in place after the nuclear agreement, could complicate the deal.
Secretary of Iran's Aviation Companies Association Maghsoud Asadi Samani, while touching upon the talks between Iranian airliners and Boeing Aircraft manufacturing company, said "Iran Air is directly holding talks with Boeing while other Iranian airlines have also conducted negotiations with the American company which are being pursued".
Boeing may need to run the sale through an overseas subsidiary and use a currency other than USA dollars in order to avoid running afoul of American laws.
He further said that the reported value of the contract worth $17 billion was not final and more details will be provided after more negotiations.
"Both sides - Iran and Boeing - have reached a written agreement for buying Boeing airplanes", Abedzadeh was quoted as saying.
He told the Fars news agency that the deal would be "the largest and most important contract" with the United States - barring military deals - since before Iran s 1979 Islamic Revolution.
Ayatollah Ruhollah Khomeini, the father of modern Iran, dubbed the United States the "Great Satan" and his successor supreme leader Ayatollah Ali Khamenei has kept Tehran on a stridently anti-American path.
Back in January, Iran signed a major deal worth $27 billion with aviation giant Airbus to purchase 118 planes from the company. Airbus needs the approval of OFAC (the US Office of Foreign Assets Control) because more than 10 percent of Airbus components are of American origin.