NEW YORK (Reuters) - Two people were shot dead at a pre-dawn Caribbean heritage celebration in New York despite ramped-up efforts by police and community activists to prevent the violence that has plagued the annual event in years past, authorities said on Monday.

A New York City police officer guards a float participating in the overnight-into-dawn celebration called J'Ouvert, ahead of the annual West Indian-American Carnival Day Parade in Brooklyn, NY, U.S. September 5, 2016. REUTERS/Mark Kauzlarich

Gunfire erupted in three separate incidents during J’Ouvert, a street party tied to the Caribbean Carnival that draws tens of thousands of revelers in the borough of Brooklyn over the Labor Day Weekend. Two other people were wounded, police said.

At the same event last year, two people were killed, including a top aide to New York Governor Andrew Cuomo.

“Last night, we had unfortunate tragedy once again affect this event,” New York City Police Commissioner Bill Bratton said at a news conference.

Two men, aged 18 and 22, were killed in shootings at about 3:45 a.m. EDT and 4:15 a.m. a.m. A 72-year-old woman was injured in the first shooting and a 20-year-old man was shot in the leg in a third shooting at about 6:45 a.m.

Only one of the victims, who were not publicly identified, was believed to have been targeted, police said. No arrests have been made.

J’Ouvert takes its name from a word in the French Creole languages of the Caribbean that means “daybreak.” The party is followed by the West Indian Day Parade, which attracts some one million people.

Last year, Carey Gabay, 43, a Harvard-educated attorney who was formerly an aide to the state’s governor, was struck and killed by a stray bullet during pre-parade festivities and another person was fatally stabbed.

On Monday, Cuomo condemned the fresh bloodshed and announced the first five winners of the Carey Gabay Scholarship Program, which was created in the slain attorney’s honor.

“As we reach the anniversary of Carey’s passing, his memory, his values, and his commitment to a better New York live on with these scholarships,” Cuomo said in a statement.

In the past decade, more than a dozen people have been either killed or wounded in shootings and stabbings at parade-associated events, according to media reports.

The New York Police Department assigned 3,400 officers to the event this year, compared with 1,700 last year.

In addition, 45 surveillance cameras were installed along the parade route, 250 light towers were erected to illuminate streets and community activists and clergy reached out to gangs leading up to the event. Police conducted a gun buy-back the Friday before the festivities.

Mayor Bill De Blasio, who declined on Monday to say whether he would consider cancelling the event going forward, said the city would need to keep strengthening security.

“I think a lot of impressive work was done,” De Blasio said. “We have more work to do.”