BEIRUT (Reuters) - Lebanese Shi’ite group Hezbollah on Friday vowed to strengthen its presence in wartorn Syria and send more leaders to the conflict, a week after its top military commander there was killed.

The death of Mustafa Badreddine, who Hezbollah said was killed near Damascus by shellfire from Sunni Islamist rebels, was one of the biggest blows yet to the Iranian-backed group’s leadership.

Hezbollah, Lebanon’s most powerful political and military group, has provided crucial support to the Syrian army, along with Iranian forces and the Russian air force. The group is estimated to have lost around 1,200 fighters in Syria’s five-year-old conflict.

“No death of any of our leaders has driven us from the battle. This precious blood will push us to a larger, stronger and more sophisticated presence,” leader Sayyed Hassan Nasrallah said in a speech broadcast live on the group’s Al Manar television.

“We are staying in Syria. More leaders will go to Syria than the number that were there before. We will be present in different forms as well,” he said without elaborating.

“We will complete this battle.”

Nasrallah spoke on a big screen, projected live in a hall in southern Beirut as part of a ceremony honoring Badreddine a week after his death.

Lebanon's Hezbollah leader Sayyed Hassan Nasrallah addresses his supporters from a screen during a rally to commemorate Hezbollah Wounded Veterans Day in Beirut's southern suburbs, Lebanon May 12, 2016. REUTERS/Aziz Taher

A military band dressed in white marched past the screen shortly before Nasrallah spoke, and men in fatigues paraded with yellow Hezbollah flags.

IRANIAN COMMANDERS KILLED

Nasrallah said Badreddine had been involved in recent weeks in the planning of an offensive to capture territory from rebels southeast of Damascus. Syrian government forces and Hezbollah fighters seized that area on Thursday, taking a substantial amount of territory from insurgents.

Badreddine directed Hezbollah’s military operations in Syria, insisting on basing himself in the country, and had been a top commander since the 1990s, responsible for breaking up Israeli spy networks and helping develop the group’s media apparatus, Nasrallah said.

He reiterated a Hezbollah statement that Badreddine was killed by insurgent shellfire, and not by an Israeli attack, following speculation after one Hezbollah figure initially blamed Israel. But he warned that Hezbollah would retaliate if Israel targeted “any of our fighters”.

At least four prominent figures in Hezbollah have been killed in Syria since January 2015. A number of high-ranking Iranian officers have also been killed, either fighting Syrian insurgents or in Israeli attacks.

Hezbollah has said it sees the Syrian war as an existential battle against Sunni extremists.

Nasrallah said the loss of commanders was not weakening the group.

Badreddine “is not the first martyr to die in this way nor will he be the last,” he said.

“We have a generation of leaders” ready to fill the void left by those killed, he said.