Iranian-backed Houthi rebels have renewed attacks on government-controlled areas in Yemen. The violence on Tuesday adds to concerns that it could reignite civil war and deepens fears over threats to regional shipping routes. With the Strait of Hormuz effectively closed by Iran, there has been renewed focus on the Red Sea and Bab el-Mandeb Strait at Yemen’s southern tip. That's an alternate route for Saudi Arabia to ship its oil to open oceans. Meanwhile, Iran's foreign minister underscored Tehran's stance that the strait cannot be reopened until the United States ends its blockade of Iranian ports and meets other demands.