Nusra Front fighter in Syria
Nusra Front fighter in SyriaReuters

The head of Syria's Al-Qaeda-linked Al-Nusra Front on Sunday said U.S.-led air strikes will not defeat Islamists in Syria and warned against retaliatory attacks against Western countries, Reuters reports.

Abu Mohamad al-Golani, in an audio message posted on pro-Nusra jihadi forums, urged European and U.S. citizens to denounce the U.S. actions if they wanted to keep out of the war.

"Muslims will not watch while their sons are bombed. Your leaders will not be the only ones who would pay the price of the war. You will pay the heaviest price," he said, warning that the battle would be brought "to the hearts of your homes".

"You should protect yourselves from this war by standing against the decisions of your rulers and stop them from bringing you the woes (of war)," he added, according to Reuters.

The United States has been carrying out strikes against “Islamic State” (IS) fighters in Iraq since August 8. It opened a new front on September 23, launching airstrikes in neighboring Syria.

Al-Golani’s threats came a day after a spokesman for Al-Nusra denounced U.S.-led airstrikes on Syria and threatened to retaliate against Western and Arab countries that took part.

"We are in a long war. This war will not end in months nor years. This war could last for decades," group spokesman Abu Firas al-Suri said.

"It's not a war against Nusra Front, it's a war against Islam,” he added.

IS and the Al-Nusra Front share the same ideology and rigid Islamic beliefs, but they fell out during a power struggle and have been battling each other this past year.

Nusra Front is now coming under pressure from its own members to reconcile with Islamic State and join forces to fight what they describe as a "crusader" campaign against Islam.

Al-Nusra Front, whose leader pledged allegiance to Al-Qaeda leader Ayman Al-Zawahiri, has been heavily involved in the fighting in Syria as well as in neighboring Lebanon, where it has claimed responsibility for several bombings and has also threatened local Sunnis.

Most recently, members of the group kidnapped 45 Fijian UN peacekeepers and threatened to try them under Islamic law before ultimately releasing them.

At least 50 fighters from the group were killed in the first wave of U.S.-led attacks in Syria last Tuesday, a British-based monitoring group said, according to Reuters.

The air assault is also believed to have killed Mohsin al-Fadhli, the leader of another al-Qaeda linked organization, the Khorasan group, which worked in league with the Al-usra Front.

Golani did not directly mention Fadhli, but said the air attacks had killed fighters whose "loss would be felt on the whole war, not just on the Front", making clear that they had suffered a significant setback.