Following an explosion at a hospital in Gaza, U.S. law enforcement agencies have increased their readiness postures in response to calls for attacks on Jewish communities and other targets in the U.S. and Europe from pro-Hamas extremists. Al-Qaeda affiliates and Hezbollah have been inciting violence against U.S. and Israeli interests, prompting the Department of Homeland Security to urge Americans to remain vigilant and report any suspicious activity. The FBI has also increased its presence in Jewish communities and is monitoring social media for potential threats.