The United States appears to be moving closer to joining Israel’s conflict with Iran with a possible strike on the country’s key nuclear facilities – including the Fordow Fuel Enrichment Plant, which is hidden deep inside a mountain.

The warning over the air base at Qatar comes as the U.S. considers whether to get directly involved in the escalating war between Israel and Iran

The United States has thousands of troops deployed on bases across the Middle East, a region in which Washington's forces have carried out repeated military operations in recent decades.Below, AFP examines countries with major concentrations of US forces in the Middle East,