Is blue-green algae a bacterium or algae?

Blue-green algae:

1. Blue-green algae are also known as Cyanobacteria and exhibit prokaryotic nature..
2. Bacteria are unicellular, prokaryotic organisms and belong to the kingdom Monera.
3. Algae are primitive unicellular or multicellular eukaryotic organisms and are placed in the kingdom Protista.
4. Thus, Blue-green algae is a bacteria.