Ordinary Iranians are increasingly worried that escalating tensions with the United States and its allies over Teheran's controversial nuclear program will lead to military conflict. Their concerns have grown as Iranian President Mahmoud Ahmadinejad has continued to defy international demands that Teheran suspend uranium enrichment, a process that can produce fuel for a nuclear reactor or fissile material for a bomb. Ahmadinejad stepped up his provocation Wednesday when he suggested Iran had in place 3,000 fully operational centrifuges used to enrich uranium - the commonly accepted number needed as a platform to begin industrial-scale production. In response to this defiance, US President George W. Bush has refused to take military action off the table as a way to halt the Iranian nuclear program, claiming Teheran is using it as cover for weapons development - a charge Ahmadinejad denies. "I'm really concerned. My family and my neighbors too," said Sepideh Akhavan, a housewife in Teheran. "It is good to defend our nuclear program but it should not lead to war because it will only bring destruction." In recent days, US defense officials have signaled that up-to-date attack plans against Iran are available if needed. No strike appears imminent, but average Iranians fear that US military operations under way in neighboring countries could provide a glimpse into Iran's future. "We see war and destruction in Afghanistan and Iraq, both of them our neighbors. I'm worried that we will be the next," said Mohammad Lofti, an Iranian bank clerk. "War will take Iran decades back." Bush suggested last month that Iran's alleged pursuit of nuclear arms could lead to "World War III." Ahmadinejad has rejected such threats as "psychological warfare" aimed at intimidating Iran to give concessions to the West. But Ahmadinejad's fiery anti-Western rhetoric has prompted criticism from average Iranians and rival politicians who are worried that his tough talk has needlessly escalated the tension. "Ahmadinejad has to be at least partly blamed for escalating tensions with the United States and its allies," said Mahmoud Mehrabi, a university student in Teheran. The Iranian president has defied two rounds of UN Security Council sanctions calling on Teheran to suspend uranium enrichment, prompting the US to advocate even stronger measures at a time when the Iranian economy is struggling. Former Iranian President Ayatollah Hashemi Rafsanjani warned the country's officials last week not to adopt positions that could endanger Iran's citizens, an apparent jab at Ahmadinejad. "Under the present sensitive circumstances, one has to avoid immaturity and not put the people in trouble," said the more moderate Rafsanjani. Another former president, Mohammad Khatami, has expressed concern that Iran's current path could mean further trouble for the country in the future. "Our country is subject to big threats. Unfortunately, there is concern that we will face greater problems," the reformist Khatami warned in comments published in several Iranian newspapers Saturday. Iran has spent billions in recent years to improve its military and develop locally made weapons as a deterrent against any possible US attack. The head of Iran's elite Revolutionary Guards Gen. Mohammad Ali Jafari warned last month that his forces were prepared to strike back with a "crushing response" if attacked, saying Washington would be "stuck in a quagmire" worse than Iraq or Afghanistan. Other Iranian military leaders have warned that Iran has prepared contingency plans for a counter strike in case of different scenarios if it is attacked by the US or Israel. These preparations provide little solace to average Iranians worried about the death and destruction that would follow a military conflict with the US. "It is appalling even to think of a war," said Mehrabi, the student. "We have suffered a lot from wars."