Heavy clashes betweenHouthi rebel troops and Yemen’s pro-government forces have killed at least 8 people, a security official confirmed Friday. The fresh round of violence comes amid heightened tensions following last week’s failure to extend a cease-fire between the warring sides. The official said exchanges of fire broke out late Thursday night in the contested western area of Yafa, killing four troops from either side and injuring five others. Local witnesses said both Houthi troops and forces under the Southern Transitional Council, which is backed by the United Arab Emirates and is a majo…