Afghan security forces and NATO-led troops clashed with suspected Taliban insurgents in southern Afghanistan, leaving up to 10 militants dead, police said on Friday. The clash in Sangin district of Helmand province occurred on Thursday, said Ghulam Nabi Mulakhel, the provincial police chief. There were no casualties among NATO or Afghan forces, he said. A blast destroyed a three-storey shopping centre in Mazar-i-Sharif on Friday, wounding at least 23 people, witnesses said. It was not immediately clear what caused the explosion in the city centre. Police and German troops from ISAF said it was likely caused by gas but witnesses said it was a bomb. “There are some soldiers from the German unit on the spot... they were called by the government and mayor,” German military spokesman Major Jurgen Fischer said. “We have not had information if this was a bomb or an attack... it seems to be a gas explosion,” he said. The force did not know of casualties.