The tension between the United States and Iran has increased since the very beginning of 2012. The Western world is imposing increasingly strict sanctions against Iran, and there is a growing call in the United States for launching a war against Iran.

Shortly after a 10-day large-scale military drill in the Persian Gulf, Iran announced plans for another large-scale exercise in the Persian Gulf and the Strait of Hormuz. At the same time, the United States and Israel plan to hold a joint missile defense exercise.

The increasing tension between the two sides has aroused wide media concern that any little conflict could erupt into a large-scale war.

The root cause of the feud between the United States and Iran is the shift in the Middle East power balance. Iran seeks regional power status, but the United States and Israel consider it a threat to their interests, thereby containing Iran through every means possible.

Iran's rise as a regional power is the most notable trend in the Middle East geopolitics in recent years, and is a result of multiple factors.

Domestically, Iran's independent technological research and development capacity keeps strengthening in recent years and Iran has made quite large progresses in many areas including the missile, warship, aviation and nuclear technology. Not long ago, Iran captured an advanced American unmanned aerial vehicle, indicating that Iran's comprehensive military strength has reached a very high level.

On Jan. 2, 2012, the Atomic Energy Organization of Iran declared that it is capable to produce nuclear fuel rod independently, indicating that Iran's nuclear technology is making progresses.

In this military drill, Iran tested and fired several new missiles too. Iran's national defense strength is much more powerful compared to other gulf states such as the Saudi Arabia, which are more willing to spend large amounts of money in purchasing advanced weapons from the United States. This powerful military strength has laid a solid national defense foundation for Iran to rise in the region.

Historically, the power shift from a large traditional country to a large emerging country was rarely peaceful. The United States always regards the Middle East as a strategically important region and one of the United States' strategic objectives in the Middle East is to prevent the rise of a great regional power.

If Iran indeed rises with the nuclear weapon in the region, the current order of the Middle East will be completely changed and the geopolitical power of the Middle East will be significant transferred. The United States will not allow it to happen.

Therefore, it is not hard to understand why the United States has been using all possible measures except for launching a direct war to contain Iran in all areas. But up to now, all these measures have not made Iran really give in and it seems that the United States currently has no better option except for launching a direct war. In this sense, the future U.S.-Iran relations may enter a "dangerous period."