NEW YORK (REUTERS) - The New York City Marathon returns to the streets of the Big Apple tomorrow after a two-year absence, with extensive security measures after the April bombings at the Boston Marathon.

Last year's 42km run was cancelled in the aftermath of Superstorm Sandy which devastated areas of New York about a week before the race.

Some 48,000 runners are expected for the renewal of the marathon which draws hundreds of thousands of people along the route.

Off the course, scuba divers will check for explosives under city bridges and helicopters will provide overhead surveillance.

Some 1,400 surveillance cameras have been added to the more than 6,000 video cameras police already watch.