The Islamic State group's secretive leader Abu Bakr al-Baghdadi purportedly released a rare message Saturday claiming that the "caliphate" is doing well despite increased airstrikes and challenging the U.S. and its allies to confront the terrorist group on the ground in Syria and Iraq. Al-Baghdadi also pledged future attacks against Israel and the West and called for an uprising in Saudi Arabia, reported Reuters.

"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," al-Baghdadi said in the 24-minute audio released on the Islamic State group's social media outlets, which was translated by Site Intelligence Group, according to The Wall Street Journal.

"Soon with God's permission, you will hear the footsteps of the mujahideen... We are getting closer to you day by day," he said to Israel, adding that ISIS has "not forgotten Palestine for a single moment."

In what was his first message since May, al-Baghdadi also taunted Western countries for their reluctance to send ground troops to Syria and Iraq, arguing that the Christians are scared to confront ISIS head on.

"Here are the Christian Crusaders and the nations of disbelief and their group with them, and behind them the Jews. They do not dare to come here on the ground to fight a small group of mujahideen," al-Baghdadi said. "They do not dare to come, because their hearts are full of fear from the mujahideen."

It's not clear when the message was recorded, but it referred to a 34-member anti-terrorism coalition formed by Saudi Arabia in mid-December, which will be based in the kingdom's capital of Riyadh and will not include Iran, Iraq or Syria, according to the Daily Mail.

"If this coalition were Islamic, it would have announced victory and aid to the people of Syria," al-Baghdadi said, calling on Saudi citizens to "rise up against the apostate tyrants, and avenge your people in Syria, Iraq and Yemen."

The message comes as the U.S. and its European allies have stepped up their airstrikes against the terrorist group as well as support for local rebels groups in Syria and Iraq, following the Paris attacks in November that ISIS took responsibility for, which killed 130 and injured hundreds more.

The intensification has resulted in the Islamic State losing ground in both Syria and Iraq in recent weeks. On Saturday in Syria, U.S-backed Kurdish militants and Arab rebels, backed by U.S. coalition planes, reportedly captured a key a dam from the group in the province of Aleppo, cutting a main supply route to the group's self-declared capital of Raqqa in the adjacent province.