NEW YORK (AP) — Tech giants Facebook, Twitter and Google are taking steps to police terrorists and hate groups on their sites but more work needs to be done, the Simon Wiesenthal Center said Tuesday.

The organization released its annual digital terrorism and hate report card and gave a B-plus to Facebook, a B-minus to Twitter and a C-plus to Google.

Facebook spokeswoman Christine Chen said the company has no comment on the report. Representatives for Google and Twitter did not immediately return emails seeking comment.

Rabbi Abraham Cooper, the Wiesenthal Center's associate dean, said Facebook...