By Roger Hardy
BBC Middle East analyst
Israel is continuing its strikes against targets in Lebanon, in an effort to weaken the Shia movement Hezbollah and prevent it using southern Lebanon as a base.
Lebanese opinion on Hezbollah may change
Last week, Hezbollah militants captured two Israeli soldiers in a cross-border raid, triggering a cycle of tit-for-tat attacks which is threatening to destabilise the region.
Why did Hezbollah act, and why did it act now? Experts have been asking this question since the group captured two Israeli soldiers last week.
And so have the long-suffering Lebanese, who have borne the brunt of Israel's military response.
The movement itself has said it acted to secure the freedom of Arab prisoners, including its own, in Israeli jails.
But that is only part of the story.
Hezbollah has a number of motives:
- It wants to strengthen its position in the Lebanese political arena, and in particular deflect pressure on it to disarm - as a UN resolution, passed in 2004, requires it to do.
- It wants to show its support for the Palestinians, and in particular for the Islamist group Hamas, and so present itself as a champion of the anti-Israeli struggle.
- Last but not least, it is sending an unmistakable message to the United States on behalf of its regional allies, Syria and Iran - squeeze us, and we will make trouble.
But, shrewd as he is, the Hezbollah leader Sheikh Hassan Nasrallah is also taking a big gamble.
First, he must calculate the impact on Lebanese opinion.
There is talk of an "axis of power" - Syria, Iran, Hamas and Hezbollah
For the past two years Lebanon has been split into pro-Syrian and anti-Syrian camps.
The anti-Syrian camp is a loose alliance of Christians, Sunnis and Druze.
Prominent among Syria's allies are the two main Shia groups, Hezbollah and Amal.
In the short run, many Lebanese seem to be venting their anger at Israel rather than Hezbollah.
But, depending on how this crisis plays out, that could change.
Hezbollah's critics, inside and outside Lebanon, accuse it of recklessness - and of pursuing a Syrian and Iranian, rather than a Lebanese, agenda.
Second, the Hezbollah leadership needs to calculate the impact of the current crisis on its regional allies.
At the moment, their interests converge.
Leaders in Damascus and Tehran are anxious to deflect pressure from the Bush administration in Washington.
The US regards Iran as a formal member of the "axis of evil" - and Syria as an informal one.
Their defiant retort is that the Americans must now take into account a new "axis of power" in the region - comprising Syria, Iran, Hamas and Hezbollah.
But what if the conflict widens still further?
For all their tough rhetoric, neither Syria nor Iran wants to be drawn directly into this fierce and volatile conflict.
The trouble with brinkmanship is that one or other player can miscalculate.