WASHINGTON, D.C. (KTVU) - The fireworks and fun of July Fourth celebrations are now a Homeland Security concern.
The FBI and U.S. Department of Homeland Security issued a nationwide bulletin to 18,000 law enforcement agencies warning of a heightened domestic terror attack threat around the Fourth of July holiday.
The symbolic day for the U.S. comes on the same week as a symbolic anniversary for the terror group ISIS, which established a self-proclaimed Islamic state on June 29, 2014 after taking control of territory in Syria and Iraq.
The terror group has since expanded its influence globally.
White House officials say the group has called for worldwide acts of violence through Islam's holy month of Ramadan which ends July 17th.
"We're mindful of the more recent call by leaders of ISIL and other extremists to carry out attacks over Ramadan which we're obviously in the middle of now," said John Earnest, White House Press Secretary.
Also of concern, three terror attacks Friday in France, Kuwait, and Tunisia.
On Monday, leaders from the United Kingdom, Germany, France, and Tunisia laid flowers in honor of the 38 victims killed in the June 26th mass shooting at a Tunisian beach resort. ISIS has claimed responsibility.
U.S. officials say ISIS has used the Internet and social media to connect with and recruit sympathizers worldwide, including in the United States.
"Al Qaeda was terror elitism. It was guidance from the top down. ISIS is terror populism. It's from the bottom up and that makes it so damnably difficult for us to detect and stop it," said retired General Michael Hayden, a former CIA Director, on Fox News Sunday.
A suspected ISIS sympathizer attacked an FBI agent with a knife in New York earlier this month and the Chairman of the House Committee on Homeland Security Michael McCaul says the FBI has arrested 10 people in the past three weeks for alleged domestic terror plots.
'I'm extremely concerned about the way the Syrian ISIS recruiters can use the Internet at lightning speed to recruit followers in the United States with thousands of followers in the United States and then activate them to do whatever they want to do. Whether its military installations, law enforcement or possibly a 4th of July event parade," U.S. Representative McCaul said.
The Secretary of Homeland Security Jeh Johnson warned U.S. law enforcement agencies and the public in a statement Friday, asking people to be vigilant.
"We will also adjust security measures, seen and unseen, as necessary to protect the American people," Johnson stated.
Rep. McCaul introduced a bill June 25th that would create a new Homeland Security program focused on domestic terror threats. It would include measures to counter online propaganda messages by ISIS.