At least six people are killed when an earthquake hit central Myanmar Sunday.<br/> <br />The 6.8 magnitude quake struck about 37 miles northwest of Mandalay.<br/> <br />Part of an unfinished bridge fell into the Irrawaddy River. Local news rpeorts say 15 people are still missing from the construction site.<br/> <br />Later this month U.S. President Barack Obama is set to become the first U.S. leader to visit Myanmar.