The NYPD is circulating a memo warning its own about continuing threats against current and former officers from terrorists and extremists.

Just this past June, three NYPD officers were attacked in Brooklyn.

One was stabbed and two were shot in what’s been described as an Islamic terrorist attack.

Back in 2014, there was a violent hatchet attack on a group of rookie cops in Jamaica, Queens, that was also deemed an act of terror.

Read more: CBS New York