The DOJ is evaluating whether it will allow the opening of overdose-prevention centers under "appropriate guardrails." Getty

Six people died after separately overdosing on heroin Sunday night within just a few blocks of each other in Philadelphia. The deaths were the latest fatalities from a spike in drug use in the city. Police had been investigating a bad batch of heroin making its way through Philadelphia and suspected possibly laced drugs in the deaths of more than 50 people in the past month alone, according to Philadelphia's Fox 29.

The city has experienced a significant uptick in drug overdoses in recent years, with almost 700 overdose deaths occurring in 2015.

"There's always going to be a crackdown on narcotics, regardless of what form it is," Philadelphia police officer Tanya Little told International Business Times. "That's a focus of ours."

Sunday's overdoses were concentrated in what the police department refers to as the East End, a division including Kensington and parts of North Philadelphia. The six deaths included men and women aged 24 to 42.

"We have that division out there patrolling and trying to combat the drug issue situation that we have here," said Little.

Philadelphia's Department of Public Health released a report in June on the near-crisis proportions of the city's opioid problem. Heroin in Philadelphia has a high purity and a low price, according to the report, and deaths from the drug have increased steadily since 2011.

A drug-related overdose death report for Pennsylvania released in July showed the death rate for overdoses in the state was 26 per 100,000 people in 2015, an increase from 21 per 100,000 people in 2014. Pennsylvania's physician general signed a standing order for the antidote naloxone in 2014 to expand its availability to friends and families of drug users. The Department of Public Health now urges all first responders, as well as family and friends to have it on hand at all times.

“The abuse of illicit street drugs and diverted pharmaceuticals continues to take too many lives and destroy families across Pennsylvania and the nation at large,” said Gary Tuggle, special Agent in charge of the Drug Enforcement Administration’s Philadelphia Division. “It is imperative that law enforcement, healthcare and treatment professionals, elected officials and community groups work together to address the factors impacting availability, use and abuse of these drugs.”