A New York City Police Department official said that beefed-up security at the New York City marathon will include sniper teams, sand truck barricades and counterterrorism officers.
Chief of Department Carlos Gomez vowed that the marathon on Sunday will be a "very safe event.''
Gomez said Wednesday that there also will be an abundance of plainclothes officers, bomb dogs and helicopter surveillance.
"We've added more sand trucks, more blocker vehicles," Gomez said. "It will be the most ever deployed at this event. We more than doubled our observation teams, our rooftop observation posts, as well as our countersniper teams from the emergency services unit throughout the boroughs, not just here in Manhattan."
New York's mayor said Sunday's marathon, with 50,000 participants and some 2 million spectators anticipated, will go on as scheduled.
"We will not be cowed. We will not be thrown off by anything,'' Mayor Bill de Blasio said.
On Wednesday, federal prosecutors brought terrorism charges against Sayfullo Saipov, the Uzbek immigrant accused in the truck rampage that left eight people dead, saying he was spurred to attack by the Islamic State group's online calls to action and picked Halloween because he figured streets would be extra crowded. He was ordered held without bail.
Information from The Associated Press was used in this report.