The Islamic State group released an audio on Thursday that it said was by its leader, urging followers to ''burn'' their enemies everywhere and target "media centers of the infidels".
The reclusive leader of Islamic State, who has only appeared in public once, also vowed to continue fighting and praised his jihadis for their valour in the battlefield - despite the militants' loss of the northern Iraqi city of Mosul in July.
This appears to be the first recording in nearly a year of the reclusive al-Baghdadi, the self-proclaimed IS caliph, apparently intended to silence rumours of his death and to galvanise his battered troops.
The recording was released by the Islamic State-run al-Furqan outlet, which has in the past released messages from al-Baghdadi and other top figures of the extremist group. The voice in the over 46-minute-long audio sounded much like previous recordings of al-Baghdadi. His last previous purported message was released in November, also in an audio recording.
Since then, the group has lost significant territory, including Mosul, Iraq, which had been the largest city under its control, and much of the group's capital, Raqqa, Syria.
In the recording, Baghdadi praised his foot soldiers for waging a tenacious battle in Mosul.
''They fulfilled their promise and their responsibility, and they did not give up except over their skulls and body parts,'' he said. ''Thus they were excused, after nearly a year of fighting and confrontation.''
He also accused the American-backed troops of using scorched-earth tactics. ''They burned the people, trees, and everything on the ground,'' he said, according to a translation provided by the SITE Intelligence Group.
Baghdadi, 46, emphasized the threat the West still faces from the Islamic State, making indirect references to recent attacks on the Underground in London, in the heart of Barcelona and in Russia.
''Now the Americans, the Russians and the Europeans are living in terror in their countries, fearing the strikes of the mujahedeen,'' he said.
The recording, which was widely disseminated to Islamic State supporters in their chat rooms on the messaging app Telegram, begins with the voice of a narrator who introduces. Baghdadi and adds, ''May Allah protect him.''
That phrase is used to refer to people who are still living and is intended to signal that Baghdadi is not dead, contrary to reports over the summer. The recording also cites current events, including the growing nuclear threat from North Korea, suggesting that it was recorded in recent weeks.
In June, the Russian military said it might have killed Baghdadi in a strike on Islamic State leaders in May near Raqqa. In July, a British-based monitoring organization, the Syrian Observatory for Human Rights, said senior Islamic State commanders had confirmed that Baghdadi had been killed in Deir al-Zour Province (See: ISIS chief al-Baghdadi dead, says rights body; US unsure).
Neither of the reports could be independently confirmed, and United States officials immediately cast doubt on their credibility.
"You soldiers of the caliphate, heroes of Islam and carriers of banners: light a fire against your enemies," said al-Baghdadi, a shadowy cleric who has been surrounded by controversy since the Sunni terror group emerged from al-Qaida in Iraq, its forerunner.
Al-Baghdadi's whereabouts are unknown but he is believed to be in Islamic State's dwindling territory in eastern Syria. The Islamic State-held cities of Raqqa and Deir el-Zour are under siege and likely too dangerous for him to hide in. Some Islamic State leadership is believed to have gone to the nearby town of Mayadeen, and the group still holds a stretch of the Euphrates River from Deir el-Zour to the Iraqi border, as well as remote desert areas along the border.
"Don't you dare allow the Crusaders and the apostates to enjoy a good and comfortable life at home while your brothers are enduring killings, shelling and destruction," added al-Baghdadi, who reminded his followers of the rewards of martyrdom, including "72 wives" from among the maidens of paradise.
"You Sunnis of Iraq, Syria, Yemen and everywhere ... get out of your beds and shake off oppression ... return to your faith and restore your glory and eminence," he said. In Yemen, Iranian-backed Shiite rebels are fighting forces loyal to the internationally recognized government, which is backed by a Saudi-led coalition.
Addressing Syria's Sunni Muslim majority, he warned them against the "cunning" of the minority Alawites, an offshoot Shiite sect from which President Bashar al-Assad hails, as well as the designs of Turkey and Assad's allies Russia and Iran.
At the peak of its power in 2014 - when the Iraqi army crumbled amid the militants' blitz - Islamic State controlled about a third of both Syria and Iraq but has steadily lost ground in the face of a US-led coalition that has backed Iraqi forces as well as Kurdish-led Syrian fighters battling the extremists across the border in Syria.
Forces loyal to Syria's Assad, backed by Russia and Iran, have also driven Islamic State out of significant territory.
Mosul was also the bureaucratic and financial hub of Islamic State. Raiding Mosul's central bank, and taxing and extorting the city's wealthy inhabitants, made Islamic State the world's richest terrorist organisation. Mosul's vast industrial zones were converted into factories for weapons and explosives.
Taking back Mosul from Islamic State came at enormous cost and destruction, especially in the western part of the city. Islamic State fighters had turned the city into a fortress, holding tens of thousands of civilians as human shields.