KABUL (AFP) - Two soldiers from NATOs International Security Assistance Force (ISAF) were killed in a bomb explosion in eastern Afghanistan, the alliance said on Saturday. NATO did not release the nationalities of the soldiers, but the fresh incident took the number of foreign troops killed in the war so far this year to 551 - the deadliest on record. Two ISAF service members died following an improvised explosive device (IED) attack in eastern Afghanistan yesterday (Friday), said a NATO press statement. Home-made bombs cause the majority of casualties among foreign and Afghan troops fighting the Taliban. The United States and NATO allies have increased the number of foreign troops fighting a nine-year Taliban insurgency to more than 152,000.