VANCOUVER -- Police in Surrey are warning the public to be careful when using drugs following an increase in deaths over the last several days.

The Surrey RCMP said Mounties were called to six deaths in just seven days, between April 21 and 27, all of which they believe to be tied to drug toxicity.

"At this time, it is unknown if the deaths are related to the use of illicit substances from the same source," the RCMP detachment said in a news release.

"However, it is suspected that the deaths are linked to the use of fentanyl/heroin (opiates)."

The RCMP says five of the deaths occurred in private homes, where it is believed the people who died were using alone.

Police did not say where the sixth person died.

There have been 70 fatal overdoses in the city that police have been called to so far this year, the RCMP said. Nearly 30 per cent of those deaths occurred in April alone.

Mounties are asking those choosing to use drugs not to do so alone. They should be careful how much they use, and ensure a kit containing the antidote naloxone is nearby.

Anyone who sees someone they believe is having an overdose is asked to call 911 immediately.

While it is not known what circumstances are behind these specific deaths, officials in B.C. have been warning the public since the start of the pandemic about the impact COVID-19 is having on the overdose crisis.

Doctors and other officials have said numerous times that border restrictions are impacting supply, meaning local dealers are having to find other sources, and users may not be getting the dose they expect.

Additionally, concerns about contracting the novel coronavirus have some hesitant to go to a hospital, and physical distancing guidelines have led to an increase in people using drugs alone.

Earlier this month, B.C. marked five years since the province declared the overdose crisis a public health emergency.

In those five years, more than 7,000 people have died of illicit drug overdose, and last year saw the highest toll yet. 

Among the actions being taken is a formal request to Health Canada for a federal exemption to decriminalize personal possession

The province has also earmarked $45 million over three years for prevention measures.

B.C.'s chief coroner said her office will undertake another death panel review of the crisis, which will include a look at the actions taken following previous recommendations, as well as "potential for innovation … to reduce or remove the dependence of so many on the perilous illicit drug market."

There are calls for more to be done, including from the advocacy group Moms Stop the Harm, which is pushing for access to a safe supply.

The majority of people who have died in B.C. are men who were using alone, or in the presence of others who were also using drugs.

Higher fentanyl concentrations have been noticed in the province, as well as an extremely addictive depressant called etizolam.

"While we know that naloxone is generally effective at reversing opioid overdoses, it is often not effective against these concoctions of opioids, sedatives, and stimulants," Chief Coroner Lisa Lapointe said on April 14. "We cannot continue with the current state. We must resolve to do much better."

With files from CTV News Vancouver's Maria Weisgarber