Storm Otto becomes hurricane off Nicaragua's Caribbean coast

(Reuters) - Storm Otto became a hurricane off the Caribbean coast of Nicaragua on Tuesday, the U.S.-based National Hurricane Center said, with additional strengthening expected over the next couple of days. Otto was 305 miles (491 km) east-southeast of Bluefields, Nicaragua, at around 1600 EST, the NHC said. The storm was packing maximum sustained winds of 75 miles per hour (121 km/h) and is expected to approach the coasts of Costa Rica and Nicaragua on Thursday, the Miami-based agency said. (Reporting by Arpan Varghese in Bengaluru; Editing by Leslie Adler)