A rise in positive COVID-19 cases in one Brooklyn neighborhood is pushing the city to take action. 

Data has shown a spike in cases specifically in the Sunset Park community. Of the 3,300 that were tested, 228 were positive. 

The city is now trying to find out the cause, and free testing was expanded with mobile units. 

People with the Test & Trace Corps are doing door knocks and making calls. The Sunset Park testing site will be open Thursday and Friday. Over the weekend, mobile testing is available at Brooklyn Herald Gospel Center. 

The city is trying to test all 38,000 households in Sunset Park. They also plan to expand testing at the Brooklyn Army Terminal starting on Monday.

The surge is only a slight increase, but city officials hope this will prevent further infection. 

"The idea is to go and do much more testing to see if it either clarifies that that was an abhorrent reality or shows us something that we can follow up on more distinctly so we're going to be out there intensely to get that answer quickly," said Mayor Bill de Blasio.

Mobile testing near 44th Street and Sixth Avenue will be open until Friday.