President Trump on Tuesday makes his first trip to California since becoming president but key arrangements remain a mystery, including to some of those responsible for keeping the peace.

He’s starting the day in San Diego to review security measures along the Mexico border and to speak to troops at Marine Corps Air Station Miramar. Then he’s headed to Los Angeles International Airport on Air Force One, the White House has announced, with a scheduled arrival at 3:30 p.m.

From there, the president travels by helicopter aboard Marine One to his next location, according to Public Information Officer Rob Pedregon with Los Angeles Airport Police.

A statement from the White House noted Trump would land at Santa Monica Airport. From there, he is expected to attend an evening fundraiser for the Republican National Committee located in or near Beverly Hills.

Freeway and surface road traffic could get congested, although — as of Monday afternoon — the Los Angeles Police Department had no information on road closures.

Mike Lopez, with LAPD Media Relations, said it is unusual that police don't have more information this close to the arrival of a president.

“We have not received any information from the Secret Service for the POTUS arrival,” Lopez said.

LAPD issued a statement last night, saying in part:

While the Department is well rehearsed at dealing with presidential visits, every administration brings with it unique challenges and new protocols, and unfortunately out of an abundance of caution many details about this visit are being withheld for security reasons. The LAPD will be heavily deployed throughout the city to ensure the safe transport of the president and secure locations he will be visiting. The Department will also be available to accommodate any residents who may feel a desire to exercise their First Amendment rights. We ask all of our residents to prepare for increased traffic with the potential of temporary street closures and delays.

Slowdowns around the airport during the president's arrival and departure should be minimal. Normal traffic will pause for just a few minutes as the president lands and takes off again, Pedregon said.

"Any time the president comes to town there is a very short closure of air traffic and the roadways surrounding the airports," he said.

Several protests and rallies, both in opposition and support of the president, have been planned in San Diego, San Ysidro and Beverly Hills.

One group, Progressive Volunteer Network Santa Monica, is organizing a "Trump Is Not Welcome Here" protest starting at 5 p.m. Tuesday at Beverly Gardens Park, corner of Santa Monica Boulevard and Beverly Drive.

It is joining another protest, sponsored by Tierra y Libertad - Union del Barrio Los Angeles, that also plans a demonstration at 5 p.m.

A rally supporting President Trump and his visit to the border is being planned in San Diego starting at 10 a.m. at 7425 Bristow Ct. Gubernatorial candidate and state Assemblyman Travis Allen is expected to be among the attendees.

If you’re hoping to catch a glimpse of Air Force One, your best bet is to watch the sky above the airport around his arrival and departure times. One popular viewing area for landings is along Imperial Highway near Main St.

President Trump will be departing LAX Wednesday morning, according to Pedregon. He is scheduled to arrive in St. Louis later in the afternoon.

This story has been updated.