'Sad day' for Afghan operations, NATO says BRUSSELS, Jan. 20 (UPI) -- Coming off its deadliest year in Afghanistan, the death of four French soldiers in Afghanistan Friday marks a "sad day" for international forces, NATO said. Four French soldiers were killed and another 16 were wounded in northern Afghanistan after an Afghan army officer opened fire following what the BBC described as a "verbal clash" with the Frenchmen. A suspect has been detained in the incident. NATO Secretary-General Anders Fogh Rasmussen said it was a regrettable reminder of the dangerous security situation in Afghanistan. "Unfortunately, this is a very sad day for our troops in Afghanistan and for the French people," he said in a statement. He offered a reminder, however, that hundreds of thousands of troops from 50 different countries were fighting and training alongside Afghan counterparts every day. French President Nicolas Sarkozy, however, said his military was suspending training operations with Afghan troops following the attack. The attack on the Frenchmen in Afghanistan follows Taliban efforts to take a step closer to reconciling with the Western-backed government of Afghan President Hamid Karzai by opening a political liaison office in Qatar. International forces have been operating in Afghanistan since 2001. Last year marked the deadliest year for French forces there with 26 reported deaths.