Gen. Martin Dempsey, chairman of the US Joint Chiefs of Staff, will visit Israel next weekend as part of a reported new and concerted American effort to prevent Israel from taking unilateral military action against Iran.Dempsey’s visit – reported in The Jerusalem Post last month – comes as US concern is growing over the possibility that Israeli military action is being planned for the near future. It will be Dempsey’s first meeting with IDF Chief of Staff Lt.-Gen. Benny Gantz as the US’s highest ranking military officer.RELATED:US Army chief concerned about Iran 'miscalculation'US uncertain Israel would advise before Iran strikeIn a recent interview, Dempsey said Israel would likely not update the US ahead of such an operation.On Friday, The Wall Street Journal reported on contingency planning by the US in preparation for a possible Israeli military strike.According to the report, the phone conversation between US President Barack Obama and Prime Minister Binyamin Netanyahu on Thursday was one of a series of messages warning Israel of the consequences of military action.Israel and the US have reportedly been at odds recently regarding the preferred timetable for a strike against Iran’s nuclear facilities. The US has said military action will become a real option only after the Islamic Republic begins building a bomb. According to some reports, Israel has warned of other so-called red lines, such as the activation last week of the new underground uranium enrichment facility near Qom. According to The Wall Street Journal, Secretary of Defense Leon Panetta and other officials have failed to receive assurances from Israel that it is not planning a military strike soon.Israel and the US are also working to finalize plans for the largest-ever missile defense drill that the two countries will hold later this year in Israel.The drill, which will involve the deployment of thousands of US troops in Israel, will last around a week and will be the first time that a top US military commander will participate in the simulations.Called “Austere Challenge,” the parties will simulate missile defense scenarios with the objective of creating a high level of interoperability so that, if needed, US missile defense systems will be able to work with Israeli systems during a conflict.This year’s drill is unique in its size and scope and will also be the first time that commander of the US European Command, Adm. James Stavridis, will participate in the simulations. In the event of war, the EUCOM commander will be responsible for approving Israeli requests to deploy US missile defense systems in Israel.On Friday, The New York Times reported that the US had used a secret diplomatic channel to tell Iranian Supreme Leader Ayatollah Ali Khameneni that closing the Strait of Hormuz would constitute crossing a “red line.”Blocking the strait, a strategic shipping lane linking the Gulf of Oman with the Persian Gulf, would constitute a “red line” for the US, as would Iranian efforts to build a nuclear weapon, Panetta said last week.During a briefing to reporters in Washington, White House Press Secretary Jay Carney said, “The United States and the international community have a strong interest in the free flow of commerce and freedom of navigation in all international waterways. We have consistently communicated our views on that subject and concerns on those issues to the Iranians and to the international community broadly.” He added, “We are engaged in the kinds of diplomatic efforts that you would expect in a situation like this.”In an interview with The Australian over the weekend, Netanyahu said he believed that international pressure and sanctions had influenced Tehran. “For the first time I see Iran wobble,” he told the Sydney-based newspaper.“If these sanctions are coupled with a clear statement from the international community led by the US to act militarily to stop Iran if the sanctions fail, Iran may consider not going through the pain. There’s no point in gritting your teeth if you’re going to be stopped anyway. In any case, the Iranian economy is showing signs of strain,” he told the paper.He added that Iran was now enriching uranium in two facilities. “I believe this is a great danger to the peace of the Middle East and the world as a whole,” the prime minister said.