Police patrol on bikes as part of security efforts at the Los Angeles International Airport Tuesday. Photo: Mao Jianjun

Los Angeles authorities have increased patrols and called for the public to be mindful of security precautions, after the Boston marathon bombing claimed three people's lives and injured more than 170 others Monday.

Michael Antonovich, Los Angeles County supervisor and Metropolitan Transportation Authority (MTA) chairman, said Monday in a statement that the MTA has heightened security and increased inspections of its bus and rail system.

"While the causes of the explosions are still under investigation, our vigilance has been raised," Sheriff Lee Baca said in a statement Monday, adding that the LA County Sheriff's Department has increased patrols at places where people congregate, such as government buildings, shopping centers, athletic events and public transit.

Sally Madera, a Los Angeles Police Department (LAPD) spokeswoman, said that the LAPD will remain vigilant at all public and sporting events where people congregate. Both the LA and Long Beach police have increased patrolling and examination spots.

The Toyota Grand Prix is about to kick off at Long Beach from Friday to Sunday, where 170,000 spectators are expected to show up. The host said that they will cooperate closely with local police and ensure the safety of all fans, staff and competitors.

The Long Beach International City Bank Marathon and Half Marathon will be held on October 13 and the committee stated that they have decided to discuss a special security plan. 

According to local Chinese media in Southern California, some Chinese-Americans joined the Boston marathon but none were killed or injured although one Chinese national was killed.

Agencies contribute to this story