A holy day in Iran marked by violence as protesters clashed with police forces about a week ago. Demonstrators have spoken out against the country's government for months now, but the clashes on the Muslim holy day of Ashura were the worst so far. At least seven people killed in the violence, though protesters and security forces disagree on how those deaths happened. Meantime, Iran's government says it's getting ready to hold a "large-scale military exercise" next month. The country says the goal is to prepare its forces to fight against an attack by the nation's enemies. There's been a lot of tension based around Iran's nuclear program. The country says the program is for peaceful purposes. Other countries, including the U.S., believe Iran might be trying to build nuclear weapons.