(Reuters) - While most Americans approve of the work being done by their local police, nearly a third feel that some officers "routinely lie to serve their own interests," a survey released on Thursday by Reuters and the IPSOS polling organization showed.

The number rises to 45 percent among African-Americans.

The findings come as scrutiny on police has been heightened in recent months by the killing of unarmed blacks by white officers, which has raised questions about police treatment of racial minorities.

While distrust is significant, nearly three-quarters of respondents approve the job done by their local police, the survey said. The survey showed that 56 percent of African-American respondents approved of their local police.

MarQuis McClee, a small-business owner from Bloomington, Indiana, who took part in the poll, said that he generally trusts police and has officers among his relatives, but as an African-American, he can also be wary around law enforcement.

"I have been involved with officers who give police a bad name," McClee, 38, said, pointing to a recent incident where he was pulled over by an officer be believes was profiling him.

Nearly 70 percent of African-American respondents believe that police target minorities.

In November, simmering tensions exploded with violent protests in several U.S. cities following a grand jury decision not to indict a police officer in the St. Louis suburb of Ferguson for shooting an unarmed black teenager.

When asked about the Ferguson police, 60 percent of respondents had a favorable impression but among black American respondents, only 32 percent had a favorable impression.

When a gunman fatally shot two police officers in New York in December in apparent retribution attack, the public was reminded of the dangers police face on a daily basis in trying to keep the streets safe.

While attention on policing has been in the spotlight, racial disparity in the criminal justice systems has become a fact of life in the United States. A study by the Sentencing Project research group showed that one in three black men are likely to be imprisoned sometime during their life. The figure for white man is one in 17.

Proactive tactics aimed at keeping crime rates down in economically stressed areas with a high number of racial minorities can also cause friction between police and minority youth who are likely to be stopped and questioned, said Larry Hoover, director of the Police Research Center at Sam Houston State University in Texas.

"There is no way that is going to be a pleasant experience, no matter how courteous an officer is," Hoover said.

(Reporting by Jon Herskovitz in Austin, Texas; Editing by Lisa Shumaker)