I wonder what's up.

The bomb squad and special weapons and tactics team have surrounded a house in south Wichita after three officers were injured in a possible explosion on Saturday afternoon.

The incident began just after 4 p.m., when officers were dispatched to check a vacant residence in the 1400 block of South St. Francis, the Wichita Police Department said in a series of tweets.

"After making entry into the residence, three officers sustained injuries from a possible explosion from an unknown device," police said.

The officers were taken to a hospital. One had serious injuries, but is in stable condition. The other two had minor injuries.

The scene remains active with the SWAT team and bomb squad at the location. The house is a few blocks northeast of the intersection of Broadway and Harry. Police have asked people to avoid the area.

At around 5:45 p.m., at least two SWAT vehicles were outside a home on St. Francis just south of the intersection with Zimmerly. One officer in tactical gear was looking out from the top hatch with a long gun pointed at the house.

Additional law enforcement officers were across the street, hunkered behind what appeared to be a personal vehicle.

Law enforcement drones flew in the sky as a surveillance plane, possibly from the Kansas Highway Patrol, circled the area. At least one K-9 unit is on-scene. Firefighters are also there, as is the Bureau of Alcohol, Tobacco, Firearms and Explosives.

A group of armored officers approached the house at around 6:20 p.m. and appeared to knock on the door. Two American flags flew from the front porch.

At around 6:30 p.m., police negotiators using a loudspeaker reassured that the injured officers would be OK. They said "we know you're scared."

"Walk outside the front door, hands up, unarmed, and you will not be harmed," police said over the loudspeaker.

Initial reports had suggested there may have been a shooting.

"It sounded like a rifle or an AR round," said Haroon Birva, a man who was outside a home down the road at the time of the incident. "I just heard one."

This is a developing story and will be updated as more information becomes available.