March 18 (Reuters) - Santander is pushing to expand its U.S. operations through a partnership with Verizon by tapping into the telecom major's vast customer base, the Spanish bank and Verizon said in a joint statement on Tuesday.

The U.S. partnership deal will allow millions of Verizon customers have access to competitive high yield savings account with Santander's new digital bank platform Openbank, they said.

"The Verizon partnership is a significant milestone for Santander as we scale our U.S. business further," Ana Botin, Santander Executive Chair said in the statement.

Santander, the euro zone biggest lender by market value, has one of the biggest auto-lending businesses in the United States. It wants to use the U.S. to build its own technology platform for consumer banking, including digital-only banking and consumer finance.

The bank formally launched its U.S. digital bank in October, offering high-yield savings accounts, which could help fund up to $30 billion in loans for vehicle purchases and broaden its retail business in the U.S.

Santander is one of the few European banks with a retail presence in the U.S. market following the exit of rivals BBVA and BNP Paribas. It has 409 branches mainly in nine states in the Northeast.

In October last year, Botin said she expected the bank to have a full-service digital bank in the U.S. by the end of 2025 - a crucial step, as Santander's U.S. business has been generating subpar returns.

Last month, the Spanish bank announced various investments amounting to over $2 billion in Mexico over the next three years. (Reporting by Rajveer Singh Pardesi, Kritika Singh and Rishabh Jaiswal in Bengaluru and Jesús Aguado in Madrid; Editing by Alan Barona and Mrigank Dhaniwala)