(CNN) -- The U.S. military has postponed planned military exercises with Israel ahead of a scheduled visit by the chairman of the Joint Chiefs of Staff, U.S. and Israeli officials said Sunday.
Gen. Martin Dempsey's trip to Israel this week comes amid growing international tensions over Iran's nuclear program and its threats to close the Strait of Hormuz to international shipping. A Pentagon spokesman said the maneuvers would be pushed back until the second half of 2012 for "a variety of factors."
"In general, leaders from both sides believe that optimum participation by all units is best achieved later in the year," the spokesman, Capt. John Kirby, said Sunday.
The exercises, dubbed "Austere Challenge 12," had been scheduled for late spring. Kirby said the delay was "not at all uncommon."
But citing unnamed security officials, Israel's Army Radio reported Sunday that holding the maneuvers at such a sensitive time could potentially result in unwanted headlines."
The news comes as U.S. officials have ramped up their warnings to Iran, which is under increasing pressure to halt its production of enriched uranium. Iran insists it has the right to peaceful nuclear energy, but the International Atomic Energy Agency has said it can no longer guarantee that the Iranian nuclear program remains peaceful.
Economic sanctions have driven down the value of Iran's currency, fueling a sharp increase in consumer prices. And U.S. observers say a covert campaign of sabotage appears to be under way against Iran's nuclear program, with a computer worm targeting its uranium enrichment plants and a string of bombings that have killed three nuclear scientists in the past two years.
Iran has blamed the attacks on the United States and Israel. And in the face of increased pressure, it has threatened to close off the Strait of Hormuz, the narrow waterway at the mouth of the oil-rich Persian Gulf.
U.S. Defense Secretary Leon Panetta warned last week that Iran would cross a "red line" if it closed the strait or built a nuclear weapon -- but he said Washington was "not involved in any way" with the assassination.
And Brig. Gen. Yoav Mordechai, a spokesman for the Israel Defense Forces, said on his Facebook page Wednesday: "I have no idea who targeted the Iranian scientist but I certainly don't shed a tear."
CNN's Guy Azriel in Jerusalem and Barbara Starr in Washington contributed to this report.