CBS News' Khaled Wassef contributed to this report.
BEIRUT - The Islamic State of Iraq and Syria has released a new message from its reclusive leader, claiming his self-styled "caliphate" is doing "well" despite an unprecedented alliance against it.
In the 24-minute audio posted Saturday, Abu Bakr al-Baghdadi said airstrikes by the international coalition only increase his group's determination and resolve.
"Be confident that God will grant victory to those who worship him, and hear the good news that our state is doing well. The more intense the war against it, the purer it becomes and the tougher it gets," he said, according to Reuters.
Baghdadi also commented on the reluctance by Western countries to send ground forces to Syria and Iraq, and argued that such countries would not dare send in their troops to confront ISIS.
"Each country is pushing in another to get it trapped ... but they do not dare come here because their hearts are filled with terror of confronting the Mujahideen ... and because they learned their lesson in Afghanistan and Iraq."
Once again, Baghdadi brought up the idea of this epic final battle which based on a 1,400-year old prophecy about "Crusader forces" attempting to conquer Muslim land in a place called "Dabiq," but Muslim armies fight them and emerge victorious. They then conquer Rome and end up ruling the entire world. According to the prophecy, this battle in "Dabiq" would be a sign marking the beginning of the end of the world. ISIS has been promoting the idea that Dabiq exists for real near Azaz, north of the Syrian city of Aleppo.
"They know what await them in Dabiq and Ghouta ... it's defeat and destruction. They know it's the final battle, and subsequently we will conquer them when they no longer could conquer us ... and Islam anew prevails over the world until the end of time."
He also mocked a recently announced Saudi-led Islamic alliance against "terrorism."
In mid-December, Saudi Arabia announced the new, 34-member alliance against terrorism, to be based in the kingdom's capital, Riyadh. But Shiite powerhouse Iran is not part of the new coalition; neither are Iraq and Syria, whose forces are battling to regain ground from the Islamic State group and whose governments are allied with Tehran.
Al-Baghdadi also warned Israel that "we are getting closer to you" every day and urged Muslims world over to join the fight, saying it is their Islamic duty to rise up everywhere.
The novelty in the latest audio, however, is that Baghdadi has admitted, for the first time, that ISIS has suffered some serious setbacks, though he claims the group remains strong.
"Then we were struck by hardship and strife ... and God's trial intensified ... so much so that the Islamic State was driven out from areas it conquered and controlled ... and the land has narrowed down on us ... to the point where the Islamic State enemies thought they defeated and exterminated it."
Research firm IHS, which has been monitoring the conflicts in Iraq and Syria, recently published an analysis suggesting that ISIS has consistently lost territory month-over-month throughout 2015. Using open source intelligence, including social media and sources inside the countries, the team at IHS estimated that ISIS' "caliphate" shrunk by 14 percent since the beginning of 2015.
Baghdadi did not explicitly threaten retaliation in the West against the airstrikes that target his men on an almost daily basis now, but he did say that those attacking ISIS will pay for their aggression.
The audio was posted on ISIS-affiliated websites and Twitter just as past ISIS messages have been. It is the first such communication since May.
Meanwhile, a U.S.-backed coalition of rebels in Syria - including Syrian Kurdish, Arab and Christian groups - has captured a major dam on the Euphrates River in the north from the Islamic State group.
The coalition, known as Syria Democratic Forces, seized the Tishrin Dam on Saturday as part of its offensive aimed at cutting supply lines between ISIS strongholds in northern Syria.
The Tishrin Dam supplies much off northern Syria with electricity.
An SDF spokesman told AP earlier this week that his forces are also trying to cut the supply lines between the Islamic State's de-facto capital of Raqqa and the group's stronghold of Manbij in northern Syria.
The SDF, dominated by the Kurdish militia in Syria known as YPG, or People's Protection Units, has become a main force in fighting IS.
And in Iraq, government forces continued their push to retake the city of Ramadi.