An Iran Air Boeing 747 sits on the tarmac at Mehrabad International Airport in the Iranian capital of Tehran. File Photo: CFP

Boeing Co signed an agreement to sell jetliners to Iran Air, the company said on Tuesday, confirming Iranian statements about the historic deal to sell 100 jetliners to the airline.

The tentative agreement, which marks Boeing's first sale to Iran since its Islamic Revolution in 1979, resulted from the nuclear accord reached last year.

The agreement brings more work to Boeing's factories in Washington state and South Carolina, and helps the aerospace and defense company catch up with a $27 billion, 118-plane order Iran placed with Airbus in January.

Boeing said in a statement that it had signed a memorandum of understanding with state carrier Iran Air, "expressing the airline's intent to purchase Boeing commercial passenger airplanes."

The Chicago-based company declined to discuss the number or type of planes it would sell, or the timetable for delivery of the aircraft.

But the head of Iran's Civil Aviation Organization, Ali Abedzadeh, told a State-run daily newspaper on Friday that the signed deal was for 100 Boeing aircraft.

Such an order would be worth about $11 billion at list prices if Iran Air bought only Boeing 737 single-aisle jetliners, and perhaps twice that much if it included a significant number of twin-aisle planes such as the 777 or 787 Dreamliner.

Boeing said earlier this year it would raise its output of 737 jetliners to 57 a month in 2019 and cut the 777 rate to seven a month in 2017 as it adjusts to shifting market demands and prepares to introduce new models.

The changes, which had been anticipated by analysts, reflected continued strong demand for Boeing's single-aisle 737, and slower orders for the twin-aisle 777.

They also came amid concerns that demand for new aircraft is slowing as the global economy cools and sharply lower oil prices make older, gas-guzzling planes more economical to fly.

Dennis Muilenburg, the CEO of Boeing, said Boeing expects a 2016 book-to-bill ratio of "approximately 1," in line with 2015, meaning new orders will roughly match deliveries.

Security concerns

Regarding the cooperation with Iran Air, a large order was expected, but the sale raised concerns among some US Congress members, who feared it could threaten national security.

Boeing's statement said the talks that led to the memorandum of understanding were conducted "under authorizations from the US government following a determination that Iran had met its obligations under the nuclear accord reached last summer."

Boeing said it would "continue to follow the lead of the US government with regards to working with Iran's airlines."

It added that "any and all contracts with Iran's airlines will be contingent upon US government approval."

US Representative Rick Larsen, a Washington state Democrat who has Boeing's biggest factory in his district, pledged to keep an eye on the deal's ramifications.

"In the coming days, the US government will be taking a hard look at the specifics of the deal to ensure it is consistent with both US interests and those of our international allies, and I'll be tracking those developments closely," he said in a statement.

US State Department spokesman John Kirby told reporters that the agency welcomed Boeing's announcement and was in close communication with Boeing.

 It also said the agreement on Iran's nuclear program reached last summer allows "civil aviation companies, including American companies, to pursue legitimate commerce with Iran."

Progress on those deals "is good … for both the economy and for public safety," he said.

Abedzadeh's statement in the newspaper on Friday confirmed a Reuters report on June 6 that Iran was close to a deal to buy more than 100 jetliners from the Chicago-based aircraft maker.

Boeing shares closed down 0.93 percent at $131.52 on Tuesday, but edged up slightly on Wednesday.

Separately, Bloomberg reported that Russian cargo carrier Volga-Dneper had placed more than 10 firm orders for Boeing 747 freighters.

Timeline unclear

Iran's interest in new planes makes sense considering the state of the country's fleet of commercial aircraft.

"Of the 250 (passenger) planes in Iran, 230 have to be replaced," Abedzadeh told the state-run daily newspaper.

Abedzadeh said that no precise timeline could be given for the implementation of the deal before an authorization is issued by the US Treasury Department.

He said Boeing had already submitted an official request to the US Treasury for a final permit for the plane sales and "the final contract is to be signed between the two sides after the license has been obtained."

In comments about the Airbus purchases, Abedzadeh told the Iran newspaper that the last obstacle is "only the permits from the US Treasury Department."