By Steve Holland

WASHINGTON (Reuters) - The United States is close to completing a series of deals to sell Saudi Arabia more than $100 billion in American arms and related maintenance, a senior White House official said on Friday, as President Donald Trump prepares to visit Riyadh in a week.

The official, who spoke to Reuters on condition of anonymity, said the arms package could end up surpassing more than $300 billion over a decade to help Saudi Arabia boost its defensive capabilities while maintaining U.S. ally Israel's qualitative military edge.

"We are in the final stages of a series of deals," the official said. The package is being developed to coincide with Trump's visit to Saudi Arabia. Trump leaves for the kingdom on May 19, the first stop on his maiden international trip.

(Reporting by Steve Holland; Editing by Yara Bayoumy and Tom Brown)