BEIRUT/JERUSALEM, Sept 25 (Reuters) - Hezbollah's flexible chain of command, together with its extensive tunnel network and a vast arsenal of missiles and weapons it has bolstered over the past year, is helping it weather unprecedented Israeli strikes, three sources familiar with the Lebanese militant group's operations said.
Israel's assault on Hezbollah over the past week, including the targeting of senior commanders and the detonation of booby-trapped pagers and walkie-talkies, has left the powerful Lebanese Shiite militant group and political party reeling.
On Friday, Israel killed the commander who founded and led the group's elite Radwan force, Ibrahim Aqil. And since Monday, Lebanon's deadliest day of violence in decades, the health ministry says more than 560 people, among them 50 children, have died in air barrages.
The Israeli military chief of staff Herzi Halevi said on Sunday that Aqil's death had shaken the organisation. Israel says its strikes have also destroyed thousands of Hezbollah rockets and shells.
But two of the sources familiar with Hezbollah operations said the group swiftly appointed replacements for Aqil and other senior figures killed in Friday's airstrike in Beirut's southern suburbs. Hezbollah leader Sayyed Hassan Nasrallah said in an Aug. 1 speech that the group quickly fills gaps whenever a leader is killed.
A fourth source, a Hezbollah official, said the attack on communication devices put 1,500 fighters out of commission because of their injuries, with many having been blinded or had their hands blown off.
While that is a major blow, it represents a fraction of Hezbollah's strength, which a report for the U.S. Congress on Friday put at 40,000-50,000 fighters. Nasrallah has said the group has 100,000 fighters.
Since October, when Hezbollah began firing at Israel in October in support of its ally Hamas in Gaza, it has redeployed fighters to frontline areas in the south, including some from Syria, the three sources said.