TOKYO (Reuters) - Mingling with more than 30,000 runners at this month's Tokyo Marathon will be a small, elite crew of police runners equipped with cameras capturing real-time footage of the course.

Japan is stepping up security measures after Islamic State in Iraq and Syria (ISIS) said they had beheaded two Japanese hostages, sparking fears of extremist-linked attacks at home.

Security for the annual race had already been tightened after the deadly bombing at the 2013 Boston Marathon, a police spokesman said.

"If police are there among the runners they may be able to see things more quickly, and runners will be able to take part in the race with a feeling of security," he added.

The 64 police runners will join thousands of law enforcers and security guards posted for protection along the route of the Feb 22 race, which is set to draw 36,000 racers and more than 100,000 spectators this year.

Signs on marathon bibs will identify the police runners, whose caps will be fitted with small cameras transmitting images of the scene to police headquarters for real-time monitoring.

The new security measures are seen as a run-through for the 2020 Summer Olympics in the Japanese capital.

Each police runner will cover part of the 42.2-km race and will be chosen from officers with extensive marathon experience.

"All police officers train as a matter of course, since you never know when you might have to run as part of your daily work," the spokesman said. "But these will be people who run quite a lot."