Iran's Supreme Leader Ayatollah Khamenei has called on world Muslims to unleash "fresh spirit" to set up a renewed Islamic civilisation across the globe. While pouring the conventional rhetoric against the US, the Iranian leader said American adversaries are relentlessly campaigning to malign the name of Islam.

Khamenei was exhorting scholars and intellectuals of the Islamic world at a gathering titled the International Islamic Unity Conference in the country. Key political figures and ambassadors of Islamic countries also took part in the meeting.

"The world of Islam, like the prophet, must unleash a new spirit and a fresh environment and set up a new Islamic civilization," he said at the summit, which was conducted to mark the birthday of Mohammad – considered as a prophet by Muslims.

He continued: "The aim of the enemies today is to set off a civil war among Muslims which they have unfortunately succeeded to some extent. They are destroying countries one after another. They are destroying Syria, Yemen and Libya. They have Muslims in Bahrain under pressure."

Khamenei said that the "arrogant powers" – in an apparent reference to western nations – are responsible for creating internal war among different denominations of Muslims. Citing former US President George W Bush, he said: "The statements of the former president [Bush] who after September 11 spoke about the war of the crusades, in fact, indicated the war between the arrogant world and Islam."

Tensions between Iran and the US (western world), have reduced in recent months after Tehran struck a landmark nuclear deal in July 2015. Nevertheless, hardliners in Iran remain wary of US and remain firm that the nuclear accord would not alter Tehran's foreign policies.

Khamenei added: "The present US officials are against the principles of Islam and unlike their statements they are after fomenting differences among Muslims and its example is creating terrorist groups like Daesh [Arabic acronym for the Islamic State] and other groups that have been created through the funding of the US affiliates and their political aids; they [US authorities] have caused the recent tragedies in the Muslim world."

Remarks from the supreme leader, who holds the highest authority in Iranian political affairs, has come at a time when it emerged that Iranian rocket passed within 1,500 yards of a US aircraft carrier in Strait of Hormuz sparking concerns.