Syrian rebel chief Salim Idriss warned on Tuesday that if fighters from Lebanon's Shiite party Hezbollah do not stop their aggression in Syria, where they are backing government troops, "we will take all measures to hunt" them, "even in hell."

"If the attacks of Hezbollah against Syrian territory do not stop within 24 hours, we will take all measures to hunt Hezbollah, even in hell," he told Al-Arabiya news channel, addressing Lebanese President Michel Sleiman, Arab League chief Nabil Al-Arabi and UN chief Ban Ki-Moon.

"I will no longer be bound by any commitments I made, if a decision to stop the attacks... is not taken and implemented," said Idriss, a brigadier general who heads the supreme military council of the Free Syrian Army.

"I can no longer restrain the fighters" of the FSA, he added without saying what concrete action they might take.

"We are being subjected to a genocide conducted by Hezbollah," charged Idriss.

"I hope that everyone will excuse the Free (Syrian) Army" for retaliating, he said.

Iran-backed Hezbollah, a close ally of Syrian President Bashar al-Assad, sent almost 1,700 fighters to the central Syrian town of Qusayr more than a week ago to support the regime's assault on the rebel stronghold.

Initially Hezbollah said it wanted only to defend 13 Syrian villages along the border where Lebanese Shiites live, and the Sayyeda Zeinab shrine near Damascus, which is revered by Shiites around the world.

However, its fighters later encircled Qusayr with regime troops before the launch of a withering assault on the strategic border town that is home to 25,000 people.