Security remains tight at the Citi headquarters after more than 100 climate activists turned up the heat on Monday.

They’re calling it the summer of heat. It was the first of four days of protests aimed at Wall Street.

According to social posts, climate activists descended upon the Citi’s main campus to protest its investment in fossil fuels that they say are killing the planet. Protesters blocked Citi employees from entering the building.  Citi press says this only lasted for a few minutes.  According to the NYPD, 23 protesters were arrested. 

Citi told News 12 in a statement: "Citi respects the advocacy of climate activists, and we are supporting the transition to a low-carbon economy through our net zero commitments and our $1 trillion sustainable finance goal. Our approach reflects the need to transition while also continuing to meet global energy needs.”

Protesters say they plan to shut down Citi for the rest of the week