A U.S. Senator from Minnesota has closed his Washington, D.C. office until after election day, fearing for the safety of his staff due to threatened acts of terrorism. Iowa Senator Chuck Grassley says he’s aware of heightened security but sees no need to close any of his offices.Grassley says he’s concerned about security but has not been told by capitol hill law enforcement the “extreme position” of closing the office is necessary, though he says he finds no fault with Minnesota Senator Mark Dayton for taking that step. Grassley says the alert that’s in place now has been there for several weeks and nothing’s changed to demand more severe steps, like closing the office. Grassley says he’s reviewed the various security issues with his staff, things like evacuation procedures and the use of gas masks. Grassley says his staff members know their responsibilities, adding, his staff is “like family” and he’d take and use whatever advice is given him from the law enforcement officials.