IS released audio of leader Abu Bakr al-Baghdadi Islamic State leader Abu Bakr al-Baghdadi says a U.S.-led military campaign against his group was failing in a speech purported to be in his name posted to the Internet. The leader of Islamic State, Abu Bakr al-Baghdadi, delivers a sermon at a mosque in Iraq. THE Islamic State group has released a defiant audio recording it says is of chief Abu Bakr al-Baghdadi, after air strikes on jihadist leaders in Iraq sparked rumours he had been wounded or killed. In the 17-minute message, the man purported to be Baghdadi vowed that IS, which has overrun swathes of Iraq and Syria, will continue to expand despite international air strikes, and that its opponents will be drawn into a ground war. Be assured, O Muslims, for your State is good and in the best condition. Its march will not stop and it will continue to expand," said the man in the recording, whose voice sounded like Baghdadi's but whose identity could not be independently confirmed. "Soon, the Jews and Crusaders will be forced to come down to the ground and send their ground forces to their deaths and destruction," he said. US President Barack Obama has announced plans to double the number of US military personnel in Iraq to up to 3100 to help advise and train Baghdad's forces - a move the man in the audio recording said was the start of the ground war between the two sides. The message was the first said to be from Baghdadi since a video released in July, shortly after IS proclaimed a "caliphate" over parts of Iraq and Syria, of the jihadist leader delivering a Friday sermon in the northern Iraqi city of Mosul. Iraqi officials and state television said al-Baghdadi has been wounded in an air strike in western Iraq. While the recording seemed aimed at dispelling speculation that Baghdadi was seriously injured or dead, it did not mention the strikes against IS leaders. But it did reference the decision by Ansar Beit al-Maqdis, Egypt's deadliest militant group, to pledge allegiance to Baghdadi and IS, which was announced after the strikes. The US said that coalition aircraft launched strikes targeting IS leaders in the area of their northern hub of Mosul on Friday, setting off a flurry of speculation that Baghdadi was wounded or killed. Some reports meanwhile pointed to another alleged strike near Iraq's border with Syria, saying Baghdadi was hit there instead. But officials in both Iraq and the United States have made clear that no one is yet certain about Baghdadi's fate. The leader of the Islamic State group said it will fight to the last man, in the strident audio recording. Pentagon spokesman Colonel Steven Warren said Monday that "the bottom line from our perspective is we simply cannot confirm his current status." And senior Iraqi officials from the interior and defence ministries and the intelligence service said investigations were ongoing. The death of the elusive IS leader would be a major victory for the US-led coalition, but with both areas where strikes were rumoured to have hit Baghdadi far from government control, confirming anything there will be difficult if not impossible. Rumours of Baghdadi's demise have surfaced before and the absence of video in Thursday's release by the IS group's media arm is likely to fuel further speculation he was indeed wounded.