Mexican soldiers killed at least 30 suspected drug-gang members in two shootouts near the U.S. border in a region that has become one of the biggest battlegrounds in the country's drug war, authorities said Friday. Twenty-five of the suspects were killed Thursday during a raid on a building in Ciudad Mier in Tamaulipas state. The other five were killed Friday in neighboring Nuevo Leon state, during a shootout on a highway leading to the border, the Mexican Defense Department said in a statement. All 30 gunmen were believed to belong to the Zetas gang-the group suspected of killing 72 migrants nearly two weeks ago in what could be Mexico's biggest cartel massacre to date. Violence along Mexico's northeastern border with Texas reached warlike proportions as fighting escalated between security forces and two feuding drug gangs-the Zetas and the Gulf cartel, former allies who split this year and started a vicious battle for trafficking routes in the area.