Recent terror alert renews concern about al Qaeda , authors say . Thirty-seven percent of cases involved anti-government extremism ; 23 % were motivated by environmental or pro-animal rights extremism ; 17 % involved white supremacist ideas or bias against particular ethnic groups ; and 11 % of cases were animated by religious bias or were acts committed on the basis of religious beliefs , including attacks against abortion doctors and providers . The Associated Press contributed to this report. Non-Islamist terrorists have been more likely to seek unconventional weapons , they say . Authors : In U.S. , Islamist terrorism no more deadly than other forms since 9/11 .
Recent terror alert renews concern about al Qaeda , authors say . The Associated Press contributed to this report. Non-Islamist terrorists have been more likely to seek unconventional weapons , they say . Authors : In U.S. , Islamist terrorism no more deadly than other forms since 9/11 .