BBC Analysis: U.S. greatest fears?

The biggest strategic fear for Washington, Israel and many Western countries is that the current crisis will turn into a regional war that will run beyond Israel's borders, according to a BBC analysis.

According to the text signed by Frank Gardner, the BBC's security correspondent, Iran has already threatened not to sit back until Palestinians are killed in Gaza.
Now there are reports in Arab media that Iranian-backed militias are moving west from Iraq and Syria to southern Lebanon, closer to the Israeli border. Some of these warriors have recent combat experience in supporting the Syrian army against the rebels.

Of all the various pro-Iranian militias in the region, Hezbollah in Lebanon is the most powerful. She fought a non-final war with Israel in 2006 and has since renovated its supply of rockets and rockets, now believed to number about 150,000.

Some of them are long and precise, enough to level entire ministries in Jerusalem and Tel Aviv if they manage to neutralise Israel's air defence. To prevent Hezbollah and Iran from joining Hamas' war against Israel, the United States has deployed two entire air carrier forces to the eastern Mediterranean.

Tensions in the region were already high before the deadly explosion at the Gaza hospital. If and when the Israeli forces launch a full-scale Gaza invasion, there is a serious danger that this could cause Hezbollah to open a new front from Lebanon.