March 24 (Reuters) - Zoox, Amazon's ( AMZN ) self-driving unit, said on Tuesday it will expand its robotaxi service in San Francisco and Las Vegas, and begin testing its purpose-built robotaxis in Austin and Miami, marking its broadest push yet into the U.S. autonomous ride-hailing market.

Alphabet's Waymo leads the robotaxi market, while Tesla has the financial resources and manufacturing scale to expand its limited service in Austin, Texas, and plans to ramp up rapidly across the United States this year.

Meanwhile, Zoox plans to significantly grow its footprint in San Francisco, focusing on dense, high-demand neighborhoods such as the Marina, Chinatown and the Embarcadero, while expanding in Las Vegas to cover more hotels and entertainment destinations along the Strip.

The company will also begin operating its purpose-built robotaxis on public roads in Austin and Miami, starting with rides for employees, their families and friends before gradually opening to the public later this year.

Zoox said it has logged nearly 2 million autonomous miles and carried more than 350,000 riders, as it introduces new features aimed at reducing wait times and improving ride experience in a crowded and fast-evolving sector.