The United States and Israel on Monday launched what one US official described as the allies' most significant joint military exercise to date, involving thousands of forces, a dozen ships and 142 aircraft, including nuclear-capable bombers. The "Juniper Oak" drills, which will run through Friday, are meant to demonstrate and deepen integration between the US and Israeli militaries, the senior US defense official said, and come at a time of growing tension over Iran's nuclear program. Although the drills will likely draw interest from Tehran, the US official said there would be no mockups of Iranian targets and that the exercises weren't oriented around any particular adversary. "I do think that the scale of the exercise is relevant to a whole range of scenarios, and Iran may draw certain inferences from that," the official acknowledged. "It's really meant mostly to kick the tires on our ability to do things at this scale with the Israelis against a whole range of different threats,” Reuters quoted the official as saying. The exercises will include live-fire exercises and involve 6,400 US forces, many of which will be aboard the US aircraft carrier George H.W. Bush strike group. Some 450 troops will be on the ground in Israel, the official said. Beyond B-52 bombers, the US aircraft will include F-35s, F-15s, F-16s and F-18s. Drills will take place over large distances, involving land, sea, air and space, the official said.