The U.S. Department of Homeland Security on Sunday urged U.S. law enforcement agencies to be on alert for possible spillover from mounting Middle East violence. “We urge vigilance during this heightened state of tension in the Middle East,” the department said in a joint assessment with the Federal Bureau of Investigation. The statement did not say there was specific or credible information suggesting an imminent threat to the United States. The assessment went to federal, state and local authorities late Friday as well as to private sector leaders, department spokeswoman Michelle Petrovich said.