The Israel Air Force held a joint drill with visiting United States pilots on Sunday, stirring interest in a region bracing for a possible armed showdown over Iran's nuclear program.

The Israel Defense Forces said the exercise was "part of a multi-year working plan involving joint flights for the purpose of mutual learning" and would be held annually.

Reports on the exercise were carried in Arab media, fuelled by speculation that Israel or the United States could bomb Iran should United Nations Security Council sanctions fail to curb its nuclear program. Iran insists its atomic ambitions are peaceful.

An IDF source said the joint air force drill was "unconnected to the current situation in the country."

Israel, believed to be have the Middle East's only nuclear arsenal, sent planes to attack Iraq's main reactor in 1981. But analysts believe Iran's facilities are too dispersed, fortified and distant for Israel to take on alone.

Defense analyst Alon Ben-David said the air force drill demonstrated recent Israeli efforts to boost military cooperation with friendly foreign states.

"Israel has realized that the way forward is to operation within coalitions, rather than alone," he said.