Iran has reached an agreement with the Boeing Company for the acquisition of new passenger planes to help modernize its outdated fleet, state-run Iranian news media reported on Tuesday.

Such an agreement, if completed, would potentially be worth many billions of dollars to Boeing and amount to the most prominent commercial transaction between an American company and Iran since sanctions linked to Iran’s nuclear program were lifted six months ago. It also would send a strong signal that Iran and the United States, despite decades of antipathy, might be moving toward normalized ties.

Numerous obstacles remain to such an agreement, most notably other American sanctions on Iran that are not related to the Tehran’s nuclear program, including a ban on using dollars in trade with the country. The restraints have dissuaded many international banks and financial companies, fearful of running afoul of American laws, from venturing into the Iranian market.

Many Republican lawmakers and others who opposed the nuclear agreement, and who have long warned of any reconciliation with Iran, could object to a Boeing deal.