Saudi Arabia, the biggest US arms customer, has chafed under those restrictions, which froze the kind of weapons sales that previous US administrations had provided for decades.

Last week, negotiators sought to complete a bilateral accord expected to call for formal US guarantees to defend the kingdom, as well as Saudi access to more advanced US weaponry, in return for halting Chinese arms purchases and restricting Beijing’s investment in the country.

Negotiators have been discussing US sales of F-35 fighter jets and other weapons to the Saudis as part of the deal, a US official said.

The potential sale of the F-35s to the Saudis was not guaranteed for a variety of reasons, but its inclusion in the discussions was significant because Riyadh has desired the stealthy fighter jet for years.