A noted US columnist on Friday criticised President Barack Obama for not addressing the two greatest threats,including Pakistan's plutonium production,at the recently concluded Nuclear Security Summit. "The first is Iran,which is frantically enriching uranium to make a bomb,and which our own State Department identifies as the greatest exporter of terrorism in the world. Nor on the agenda was Pakistan's plutonium production,which is adding to the world's stockpile of fissile material every day," wrote Charles Krauthammer,a columnist at The Washington Post. "Pakistan is a relatively friendly power,but it is the most unstable of all the nuclear states. It is fighting a Taliban insurgency and is home to al-Qaeda," he said in his comments. "Suicide bombs go off regularly in its major cities. Moreover,its own secret service,the ISI,is of dubious loyalty,some of its elements being sympathetic to the Taliban and thus,by extension,to al-Qaeda," he wrote. Acknowledging that sequestering nuclear material is a good thing,he wrote: "But,it is a minor thing,particularly when Iran is off the table and Pakistan is creating new plutonium for every ounce of Canadian uranium shipped to the United States."