Chairman of the US Joint Chiefs of Staff Gen. Martin Dempsey is concerned that the US will get drawn into conflict with Iran, and said the United States is collaborating with Israel on the Iran issue during an interview with CNN Wednesday."My biggest worry is they will miscalculate our resolve," Dempsey said, referring to Iran. "Any miscalculation could mean that we are drawn into conflict, and that would be a tragedy for the region and the world.""We are trying to establish some confidence on the part of the Israelis that we recognize their concerns and are collaborating with them on addressing them," he continued.Dempsey went on to say that the US is "of course" using a variety of means to gather intelligence on Iran. "It would be rather imprudent of us not to try to understand what a nation who has declared itself to be an adversary of the United States is doing," the general said.Following a meeting on Tuesday, diplomats from the United States, the European Union and other allies agreed to step up pressure on Iran to force it to resume talks over its nuclear program, an Italian diplomatic source said.The diplomats from the so-called "group of like-minded nations" met in Rome to discuss further sanctions against Iran, which could include a possible EU oil embargo.RELATED:'Iran could assemble nuclear bomb in under a year'Iran says invites UN nuclear agency to visit"The participants repeated the need for Iran to conform to resolutions of the United Nations and the IAEA (the UN International Atomic Energy Agency), and asked the country to satisfy demands by the international community for timely and immediate clarifications on its nuclear program," the source said.Iran faces tightening sanctions over a nuclear program it says is for peaceful power generation, but which its foes suspect is aimed at developing nuclear weapons.The group includes the United States, the European Union and several European nations, Australia, Japan, South Korea and other countries but it was not clear if all of them were represented. The United States also attended.The small informal group has been meeting for two years and its goal is to share information and discuss the next steps in the sanctions process. The United States has long banned Iranian crude oil imports and last week Congress voted through restrictions on dealing with the Iranian central bank.The White House must decide whether or not to grant waivers to major Iranian oil importers like China, India and South Korea that need to deal with the bank to pay for Iran's crude.