Airbus and Boeing announced Wednesday that they received US licenses to sell planes to Iran Air, clearing the way for the first western aircraft sales to the country in decades.

The approvals from the US Treasury Department allow both aerospace giants to proceed with sales worth billions of dollars into a country that had been entirely off limits prior to the landmark 2015 nuclear deal.

"We have issued the first two licenses for the export of certain commercial passenger aircraft to Iran under this new policy -- to Boeing and Airbus," said a Treasury spokesperson.

"These licenses contain strict conditions to ensure that the planes will be used exclusively for commercial passenger use and cannot be resold or transferred" to any Iranian entity still under US sanctions, the spokesperson said.

The approval allows Boeing to fulfill its June memorandum of agreement (MOA) with Iran Air that covered the sale of 80 planes, consisting of the single-aisle 737 and the long-range 777.

Boeing will also lease 29 other planes to the Iranian national carrier under the deal.

"We applied for a US government license that would allow us to complete the sales anticipated in the MOA," said Boeing spokesman Marc Sklar. "We have received that license and remain in talks with Iran Air based on the MOA."

The deal is estimated to be worth roughly US$25 billion. The Boeing sales would be the first from a US aviation company to an Iranian entity since the 1979 Islamic revolution.

Additional sales would require another license, said a person familiar with the matter.

Airbus struck a similar preliminary agreement in January to sell Iran 118 aircraft, but it also required US approval because some of the planes' components are made in the United States.

The deal includes the single-aisle A320 and the long-range A330.

An Airbus spokesperson said it had received the first of two licenses applied for on Tuesday and expected the second one "in the coming weeks".

The Airbus deal was initially valued at US$25 billion (22.4 billion euros) but Iranian officials say it is worth nearer US$10 billion.

Neither Airbus nor Boeing has announced a schedule for delivering the planes.

Before the nuclear deal under which Iran has curbed its atomic program in return for a lifting of international sanctions, an embargo dating from 1995 prevented Western manufacturers from selling equipment and spare parts to Iranian companies.

The restrictions, which have been blamed for crippling the industry, were partly lifted by an interim agreement on Iran's nuclear program that came into force in January 2014.

Iran's current commercial aviation fleet, which has a poor air safety record, numbers around 140 planes with an average age of around 20 years, with many in desperate need of replacement.

Iran projects a demand for between 400 and 500 commercial airliners over the next decade.

Boeing's deal with Iran drew scorn from some on Capitol Hill. Lawmakers on a panel in the House of Representatives enacted a measure to block the sales, but it did not win support in the full Congress.