More exhausting than a five-setter: Protecting the US Open

NEW YORK (AP) More than a half million fans over two weeks are expected at this year's U.S. Open tennis tournament and security officials are ramping up efforts to make the grounds safer than ever.

Authorities this year fortified fencing near a grandstand stadium at New York's Billie Jean King National Tennis Center so it can withstand a crash from a car bomb.

Security director Michael Rodriguez says that's one of many measures aimed at protecting the event, which begins Monday.

Rodriguez oversees a private security force of 300 officers.

He is expecting a larger-than-usual show of force this year from the New York City Police Department in the wake of attacks in Europe and mass shootings in the United States.

About 700,000 people are expected at the U.S. Open this year.