Ali Qara Daghi, Secretary-General of the Qatar-based International Union of Muslim Scholars (IUMS), told AFP late Wednesday that Trump was also using "attacks on Islam" to try and secure his bid for the White House.
"This is really annoying us so much that he has these levels of support," he said.
"We do not want this for the American people or America, which was founded on democracy, freedom and pluralism.
"His remarks are not consistent with common sense or moral values because he is not honest and exploits attacks on Islam in order to gain access to power," Qara Daghi added.
The IUMS is an influential but controversial organisation based in Doha.
It is headed by Yusuf al-Qaradawi, considered a spiritual guide to Egypt's Muslim Brotherhood, who were ousted from power in the North African country in 2013 and later blacklisted.
Signup to our newsletter and follow us on Facebook and Twitter!
During his campaign, Trump notably called for Muslims to be banned from entering the US amid concerns over security.
He initially made the proposal following the San Bernardino attack last December, when Syed Farook and his wife Tashfeen Malik killed 14 people in California before they died in a shootout with police.
Despite widespread condemnation, Trump's contentious proposal has not impacted on his electoral chances.
He leads the Republican race with the backing of 743 delegates, some 200 ahead of his closest rival Ted Cruz.
A total of 1,237 delegate votes are needed to secure the Republican nomination.
The next primary takes place on April 19 in Trump's native New York.
The US presidential vote takes place on November 8.