State Department issues travel alert "to and throughout Europe"

BRUSSELS --The Obama administration stepped up security at major transit hubs across the country after Tuesday's airport and subway bombings in Brussels, as top U.S. intelligence officials warned of the risk for copycat attacks at home. President Barack Obama vowed to help Belgium track down those responsible for the deadly explosions. Homeland Security Secretary Jeh Johnson stressed there is no "specific, credible intelligence" pointing to a similar plot in America, but he said the Transportation Security Administration would deploy additional security at major airports and rail stations in different cities. Officials also reviewed additional security measures for travelers from Belgium, among more than three dozen countries whose citizens generally don't need a visa to enter the U.S. The State Department warned Americans about potential risks to travel in Europe. "Terrorist groups continue to plan near-term attacks throughout Europe, targeting sporting events, tourist sites, restaurants and transportation," it said in a statement. Officials advised U.S. citizens to "exercise vigilance" in public places or on mass transportation and to take "particular caution" during religious events or large events. More...