St. Louis ? At least two people have died because of recent blistering temperatures across the Midwest, and health officials urged residents Tuesday to keep an eye on those who could be vulnerable as the mercury continues to rise.

The National Weather Service issued excessive heat warnings for portions of Missouri, Arkansas, Kansas and Oklahoma through tonight.

Forecasters said temperatures would approach 110 degrees in some areas. By late afternoon, they had already topped 100 degrees in many areas, including 101 degrees in Oklahoma City, 102 degrees in St. Louis, and 106 degrees in Wichita.

Little Rock, Ark., hit 107 degrees, breaking the previous record of 104 degrees set in 1987.

Compounding that, the high humidity common to the region in the summer could make it feel 10-15 degrees hotter than the thermostat reading.

“Today and tomorrow are going to be pretty nasty,” National Weather Service meteorologist Ben Miller said.

The Kansas City, Mo., Health Department said heat was likely to blame in the deaths of two people, but did not release their names or other details, saying the deaths were under investigation.

Emergency Medical Services Authority in Tulsa, Okla. reported seven heat-related calls on Sunday, none of them life-threatening.

“With the heat expected to continue this week, residents need to check on neighbors, friends and relatives as heat-related illnesses and deaths can be prevented,” said Dr. Rex Archer, Kansas City’s health department director.

People who don’t have air conditioning were urged to try to get somewhere that does, or at least keep their homes well ventilated with fans. Those who work outside were urged to be extra careful.

St. Louis topped 100 degrees for the first time since Aug. 15, 2007.

“It’s August,” Miller said. “We’ve got a ways to go yet.”

On Monday, the 108-degree reading in Wichita broke the city’s old record of 106 degrees, set in 1970.

Arkansas was sweltering, too. Monday highs reached 107 degrees in Blytheville and 106 in Little Rock. Freedom, Okla., felt temperatures rise to 109 degrees, while it was 108 and 107 elsewhere in the state. Missouri was hottest in the southwest corner of the state — Mt. Vernon reached 104 degrees Monday.

The Arkansas Forestry Commission said Tuesday that firefighters had fought 13 wildfires that burned 219 acres since Monday afternoon.

Late Tuesday afternoon, crews were still working to contain one fire in northern Conway County. Air tankers were dropping water on that fire, as they did with a Van Buren County fire that was brought under control.

Earlier, water service was knocked out in Van Buren County when the water utility’s pumps failed. The Arkansas National Guard began to supply water tanks on Monday. By Tuesday, soldiers had trucked over 9,000 gallons of water for residents, including a 5,000-gallon tank for the county’s hospital in Clinton.

Clinton Mayor Roger Rorie said at 5 p.m. Tuesday he had just arrived in town with the parts the system needs and residents should have water by this morning.

Burn bans were issued for 11 Arkansas counties. The Forestry Commission said the state is at moderate risk of wildfires and urged residents in rural areas to take precautions. Burning is strongly discouraged across the state. The 100-plus degree temperatures combined with low humidity in places made wildfires more likely.