American officials have suddenly raised the stakes in the long-simmering tensions between the United States and Iran, pointing to new intelligence that they say suggests an imminent threat to American interests in the Middle East.

The potential for armed conflict between the two countries has loomed since the Islamic Revolution and takeover of the American Embassy in Tehran four decades ago. Occasionally, those tensions have escalated into violence.

The recent American assertion that Iran poses an immediate threat has raised fears that the two nations have pushed closer to the brink. Here’s what you need to know about the risks of a broader conflict.

How did we get here?

Earlier this month, the United States — pointing to information about an imminent threat of an Iranian attack in the Middle East — swiftly moved an aircraft carrier group into the region. In quick succession, it then shored up defenses and evacuated personnel from the embassy in Baghdad, the Iraqi capital.