DUSHANBE, May 26 (AFP) - Russian border guards stationed in Tajikistan killed two drug traffickers and wounded a third in a shootout Wednesday morning on the border with Afghanistan, the Russian border service said. The Russian guards seized 16 kilograms of heroin and two Kalashnikov machineguns from the smugglers, all Afghan nationals, who were attempting to enter Tajikistan by crossing the Pyandzh river some 150 kilometers (90 miles) south of the capital Dushanbe. Russia has several thousand border guards patrolling the Afghan border in the former Soviet republic in accordance with a joint Russian-Tajik agreement. The military stations are largely engaged in battling the region's bustling drug trade, which authorities have said exports heroin to Russia and Central Asia from laboratories in Afghanistan. Since the start of the year, Russian guards have killed 25 Afghan smugglers in border shootouts, confiscating more than 200 kilograms of heroin.  