Fifa World Cup matches set to be held across the United States face heightened terrorism risks, with experts warning that vulnerabilities are being amplified by the US-Israel conflict with Iran and a depletion of counter-terrorism expertise within federal law enforcement. The biggest threat stems from homegrown violent extremists, often lone actors that may have become radicalized online by extreme political views or jihadists such as the Islamic State (Isis), said four counter-terror experts interviewed. “We need to protect not only each venue, but all the other links in the chain that get to the point of the game,” said Javed Ali, associate professor at the University of Michigan, who previously served in the FBI , Department of Homeland Security, and as national security council senior director for counter-terrorism. “There are just so many games.…