UPDATE 1-Los Angeles officials brace for Jackson memorial

* Demand for tickets crashes server

* Los Angeles to Jackson fans: Stay home

* Memorial service, cost shrouded in mystery (Updates throughout with quotes, police staffing)

By Bob Tourtellotte

LOS ANGELES, July 3 (Reuters) - Los Angeles city officials are planning a massive security operation for Michael Jackson's public memorial service next week, and on Friday urged fans who do not win a ticket in a random drawing to stay away from the basketball arena where the singer will be memorialized.

Organizers have set aside a total of 17,500 tickets through an Internet-based lottery for the televised service at the Staples Center, and for a closed-circuit screening at the nearby Nokia Theater.

Within minutes of the system being announced at a news conference, the computer system crashed. Officials warned additional disruptions were likely as fans from around the world applied for tickets.

"You might want to consider watching this from the comfort of your own home," said Los Angeles City Councilwoman Jan Perry, who is doubling as the city's acting mayor.

A wide area around the venues in downtown Los Angeles will be blocked off for the 10 a.m. (1700 GMT) event. Both local and state law-enforcement agencies have been marshaled for duty.

A local news-radio station reported that more than 1,400 officers from the Los Angeles Police Department alone have been asked to volunteer for duty on Monday and Tuesday. The LAPD, which has about 9,000 officers in total, declined to comment on the report or to reveal a staffing number.

A Jackson family spokesman also declined to provide details of the memorial service, but said there would not be a funeral procession and Jackson's body would not be at the memorial.

Funeral arrangements have not been disclosed, but security has been beefed up at the Forest Lawn Hollywood Hills mortuary, where his body is believed to be held.

Officials were also tight-lipped about the cost of the memorial service, and who would pay for it.

Like other U.S. cities, Los Angeles is strapped for cash in the global recession and similar questions about public tax revenues being spent for such an elaborate ceremony surfaced last month when a $2 million celebration was given for the champion Los Angeles Lakers professional basketball team.

That event, which attracted over 500,000 people, was eventually funded through private donations.

The city has already budgeted for LAPD overtime, Perry said, adding that officials would "deeply appreciate" help to offset incremental costs, such as transportation, sanitation and staging.