PORTLAND, Ore. (KOIN) — The Oregon State Medical Examiner’s Office has received reports of four suspected heat-related deaths this week since the start of the July heat wave, Oregon State Police announced Thursday afternoon.

However, the medical examiner’s office says none of the deaths can be confirmed as heat-related yet, state police added.

Three deaths occurred in Multnomah County on Monday, Wednesday and Thursday, while one took place in Umatilla County on Tuesday.

Portland Mayor Ted Wheeler released a statement regarding the Multnomah County deaths on Thursday afternoon, saying his office is awaiting additional information from the county medical examiner.

“We are continuing to work closely with our partners at Multnomah County to provide support to Portlanders during this emergency,” Wheeler’s statement read. “I urge those who are impacted by the high temperatures to seek refuge in one of the available cooling shelters and community spaces.”

The state examiner’s office says that the designation of a heat-related death is preliminary and further investigation may reveal a cause of death that’s unrelated to hyperthermia.

They also said that the final determination of the cause of death may not be known for several months after the death.