Under Armour CEO Kevin Plank is defending Baltimore after President Donald Trump called the city a "disgusting, rat and rodent infested mess."

Plank posted a video ad to his personal Instagram account on Sunday that highlights the sportswear company's Baltimore roots.

He posted a caption with the video that read: "On behalf of the thousands of UA Teammates who proudly call Baltimore HOME... Work to be done but we are of this city and for this city. #WeWill #StandforBaltimore #hometownproud #410 #teamua."

Read more: Here's how Under Armour grew into a $15 billion athletic-apparel empire

Plank has previously expressed support for Trump. In a 2017 interview with CNBC, Plank called Trump "pro-business" and a "real asset."

Plank's Instagram post comes after Trump posted a series of tweets over the weekend attacking Baltimore and Democratic Rep. Elijah Cummings, whose Maryland district comprises over half of the city of Baltimore, as well as parts of Baltimore and Howard counties.

"Cumming District is a disgusting, rat and rodent infested mess," Trump tweeted. "If he spent more time in Baltimore, maybe he could help clean up this very dangerous & filthy place."

Trump also called the city violent and said "no human being would want to live there."

Plank and Under Armour have deep roots in the Baltimore area.

Plank was born in Kensington, Maryland, which is located less than 40 miles from Baltimore, and he attended the University of Maryland. He founded Under Armour in 1996 in his grandmother's townhouse in Washington, DC, then two years later moved the company to Baltimore.

Under Armour's headquarters is housed in a former Procter & Gamble factory in Baltimore's Inner Harbor.