Five paramilitary troops and six drug smugglers were killed in a clash on Thursday in Chaghi, officials said. The gunfight broke out when security forces intercepted a gang of drug traffickers 300 km (185 miles) west of Quetta, capital of south-western Balochistan province.
"It was a heavy fighting that lasted for more than two hours. Our five soldiers were martyred and six smugglers were killed," a military official, who asked not to be identified, told Reuters.
Earlier, in the day, paramilitary troops seized more than 1,000 kg (2,200 lb) of hashish and 96 kg (210 lb) of morphine in two raids in Zhob and Dalbandin towns.
Most of the world's opium is produced in Afghanistan, where Taliban fighters have allied with drug runners to fight Afghan and Western forces trying to extend the Kabul government's authority into the lawless south.
Pakistani officials say about 70 percent of Afghanistan's drugs are smuggled through Pakistan and Iran, while the rest goes north through Central Asia.
Pakistan itself is trying to achieve status of a poppy-free country by the end of the year.