Iranian President Mahmoud Ahmadinejad said on Monday the United States could no longer dictate policy to the rest of the world and that relations between NATO and Pakistan would become more unstable."NATO and the United States should change their policy because the time when they dictate their conditions to the world has passed," Ahmadinejad said in a speech during a conference on Afghanistan's economy in the capital of neighboring Tajikistan.Iran was not participating in a nuclear security summit which began in Seoul, Korea on Monday.Speaking ahead of the summit at the University of Seoul on Monday, US President Barack Obama said that time was running out to resolve Iran's nuclear standoff with the West."Once again, there is the possibility of a diplomatic resolution that gives Iran access to peaceful nuclear energy while addressing the concerns of the international community," Obama stated."Today, I'll meet with the leaders of Russia and China as we work to achieve a resolution in which Iran fulfills its obligations," he added."Relations between NATO and Pakistan, their unsteadiness and instability, will only grow," he said. He was speaking in Farsi, which was translated into Russian for conference participants in the former Soviet republic.Calling for the immediate withdrawal of foreign troops from Afghanistan, Ahmadinejad said: "The main reason for the difficulties in the world is the policy of NATO member countries, undertaken with the aim of reviving colonialism.""The entire problem lies with NATO and with the policies of NATO members, most of all the United States, which entered Afghanistan under the guise of the war on terrorism and under the same banner is now surrounding India, Russia and China."The US delegation to the conference, headed by Assistant Secretary of State for South and Central Asia Robert Blake, left the hall when Ahmadinejad began to speak and returned after the conclusion of his speech.Ahmadinejad made no reference to Iran's nuclear program. Iran says the program is purely peaceful, but Israel and Western nations believe the country is moving towards a nuclear bomb that could change the regional balance of power.