The bureau cited spikes in both "reporting on potential hate crimes or other criminal violations" and "hoax bomb and active shooter threats," the latter targeting synagogues.
Eyewitness video showed heavy smoke rising from the area; Buffalo airport cancels all flights as FBI investigates.
The FBI director stressed that while heightened vigilance is required "it is by no means a time to panic."
If convicted, Abuayyash could face up to 15 years in federal prison and a possible $250,000 maximum fine.
The Fremont County sheriff described the scene at the funeral home as “horrific.”
The FBI says Nunez Santos, who is Peruvian, embarked on the bomb threat spree after asking teen girls to send him pornographic pictures of themselves and being rejected.
China says its space program is for peaceful purposes, but US military officials say Beijing sees space as crucial to its military strategy.
The shooting occurred as FBI agents attempted to serve arrest and search warrants at a home in Utah, where President Biden was scheduled to visit on Wednesday.
De Oliveira, 56, told another worker at the resort where Trump lives that "the boss" wanted security videos of the property in Florida deleted after the Justice Department subpoenaed them.
Court documents reveal that Al-Azhari, a US citizen who had spent a significant portion of his life abroad, adopted extremist Islamist/Salafist beliefs.