Well-wishers put flowers on a squad car parker outside the Des Moines Police Department after two police officers were shot and killed in separate attacks described as "ambush-style" in Urbandale and Des Moines, Iowa, November 2, 2016. [Photo/Agencies]

DES MOINES, Iowa - Two Iowa policemen were shot dead on Wednesday in ambush attacks while sitting in their patrol cars, and a suspect who had a recent run-in with officers after displaying a Confederate flag at a football game was taken into custody, authorities said.

The suspect, 46-year-old Scott Michael Greene, was being held in connection with the killings that occurred shortly after 1 a.m. in the Iowa capital Des Moines and its affluent suburb Urbandale, police said.

The slain officers were identified as Sergeant Anthony Beminio, 38, of the Des Moines Police Department and Officer Justin Martin, 24, of the Urbandale Police Department.

Urbandale Police Chief Ross McCarty said Greene, who has not yet been charged, was well known to local police after various past incidents. Greene had a confrontation with police last month after waving a Confederate battle flag, a racially charged symbol, in the crowd while the national anthem was played at the start of a high school football game, McCarty said.

Martin's body was discovered outside the stadium where the flag incident took place. Greene is white, as were both slain officers, Des Moines police spokesman Paul Parizek told a news conference.

"There's nothing to indicate right now that there was anyone else involved," Parizek said.

The shootings represented the latest attacks on police in the United States during a time of intense public debate over race and law enforcement in America. Some 52 U.S. police officers have been fatally shot while on duty this year, up 58 percent from the 33 shot dead by this point in 2015, according to the National Law Enforcement Officers Memorial.

Police said they found the first slain officer's body at about 1:06 a.m. in Urbandale, and the second about 20 minutes later about two miles (3 km) away in Des Moines.

A police cruiser at the site of the Des Moines shooting could be seen with three bullet holes.

"These officers were ambushed," Parizek said.

A 10-minute video posted on YouTube last month by a user calling himself Scott Greene showed an interaction with officers over the flag incident. A voice, apparently Greene's, is heard complaining to police that "African-American people" took the flag from him in the stands and "assaulted" him, and saying he wanted to press charges.

The Confederate flag is a racially charged symbol for its association with the pro-slavery South in the U.S. Civil War.

"There were people in the crowd who felt that was offensive, and that he should be removed from the stadium," McCarty said.

Police officers shown in the video said he was removed from the stadium because he caused a disturbance.

"You have to understand, in the current social climate that we're in, when you fly the Confederate flag standing in front of several African-American people, that's going to cause a disturbance, OK, whether you intended to or not," a female officer is heard telling the man in the video.

McCarty said high school officials banned Greene from the property following that incident, but had been trying to determine how to enforce the ban given that Greene has a daughter attending the school.