Emergency search for young girl reported missing in Thames River underway in London, Ont.

First responders in London, Ont., are searching the Thames River after reportsthat a young girl entered iton Thursday afternoon.

Swimmers and boats in the water near the intersection of Adelaide Street and Kipps Lanehave been searching since approximately 3 p.m. ET.

London police have also deployed a drone over the area.

"We had a call come in of a child seen struggling and [going]under," saidJeff Johnston, acting district fire chief. "We've been searching exhaustivelyand the crews are going to remain here until we find something."

There are no details on the age of the child, but the emergency call, according to fire officials, came from the mother.

A woman confirmed by several members of the community to be the missing child's mother was seen at the scene talking to police.

About a dozen church community members who were at the scene for support said the mother was there with her three children, and the family is from the Philippines.The church members also said the young girl, who is believed to be about seven years old, ventured off while the mom was busy with the younger children.

Adelaide Street wasreduced to one lane in both directions from Kipps Lane to Windermere Road for several hours as firefighters used an elevated ladder to scan the surface of the river from the bridge. As of 6:15p.m., the lane closures were no longer in effect.

"We are asking the public to avoid the area to allow emergency crews to continue to search for the child," said Const. Matt Dawson with the London Police Service.

Emergency crews from other areas, including Waterloo police, have been called in to assist with the search,Johnston said.

"The dam at the Fanshawe Conservation Area has been shut down to help reduce the water levels in the river so we can have a better vantage point," said Johnston.

On Tuesday, the London Fire Department conducted various water rescue training exercises in the Thames River, but didn't expect to be putting them into practice so quickly.