Tajikistan officials say border guards have killed eight Afghan drug smugglers trying to sneak into the country. The officials say troops patrolling the southern border spotted a group of 12 people crossing a river dividing the two countries. They say gunfire broke out and eight drug carriers were killed while the remaining four managed to return to Afghan territory. A large quantity of drugs and weapons was later found at the site of the clash.Tajikistan shares a 1300-kilometer border with Afghanistan. The Central Asian country has become one of the main routes for illegal drugs entering Russia and Western Europe from Afghanistan, the world's largest producer of opium.