Recent high-profile shootings between police and blacks have raised tensions in the US, made policing riskier and increased many officers' reluctance to carry out some of their duties, according to a survey of police opinions published on Wednesday.

The Pew Research Center survey found about three-quarters of officers view a series of deadly incidents between police and blacks in recent years as having increased tensions and made their departments less willing to stop and question suspicious persons.  86 percent said the deadly encounters have made police work more difficult.

The shooting of an unarmed black man by a white police officer in Ferguson, Missouri, in 2014, triggered massive protests and renewed debate over police tactics and their relationship with the communities they are supposed to serve. A spate of other killings of mostly black men - in Baltimore, New York, Chicago, Milwaukee and other cities - strengthened the Black Lives Matter movement and prompted the Obama administration and police departments across the country to review law enforcement-community relations.

Police feel 'respected by the public'

While public protests and other surveys have provided a glimpse of the public's view of police, the Pew survey of nearly 8,000 policemen and women from departments with more than 100 officers is the first to measure the opinion of law enforcement on a large scale.  Conducted between May 19 and August 14 last year, part of the survey was conducted after eight officers died in separate attacks in Dallas and Baton Rouge last July.

Ninety-four percent of officers say they are concerned about their safety, but only 14 percent believe the public understands the risks they face. That contrasts with 83 percent of Americans who in another Pew poll said they understood the risks facing law enforcement.

Still, most police officers feel respected by the public and trust most people. "Rather than viewing the neighborhoods where they work as hostile territory, seven in ten officers say that some or most of the residents of the areas they patrol share their values," Pew said.

Racial divisions

But the results show existing divisions between white and Hispanics on one side and blacks on the other. A little over two-third of officers said that protests in the wake of police shootings were driven by anti-police bias, while only 10 percent were of the view demonstrations are driven by a desire to hold police accountable.

Significantly, two-thirds of police say that the high-profile deaths were isolated incidents and not symptomatic of a broader problem between police and blacks. That contrasts with another Pew survey that found 60 percent of Americans view the violent encounters as part of a broader policing problem.

Another finding of the survey was that while a large majority of officers say police have a good relationship with whites, Hispanics and Asians, just 56 percent say police relations with blacks are good.

On nearly all survey questions, the view of black and white police officers diverges. "Differences between the views of black and white officers mark one of the singular findings of this survey," it said. For example, while six in ten white and Hispanic officers say relations with blacks are excellent or good, the same view is shared by only 32 percent of black officers. 

Similarly, about a quarter of white officers say protests following police shootings of blacks were driven by a desire to hold police accountable, but around seventy percent of black officers thought the protests were to call for greater accountability. On the broader issue of race in the US, 92 percent of white officers compared to only 29 percent of black officers are of the view that the country had done enough to ensure equal rights for blacks.

Only a third of all officers responded that in the past month they had have physically struggled or fought with a suspect. Again though, there was a difference between white and black officers, with 36 and 20 percent, respectively, having physically struggled or fought with a suspect. White and Hispanic officers, meanwhile, are more likely to be verbally abused by the community than black officers.

Overall, 56 percent of officers believe some neighborhoods require a more aggressive stance rather than a courteous approach. Slightly less than half of officers say some people can only be brought to reason with some degree of force.