Despite being a relatively small constituency, Muslim voters in the United States could have a key role in the presidential election.

The number of swing states in the US is notoriously low and some, such as Florida and Virginia, have small but potentially significant Muslim populations which could prove decisive come the November polls.

At least that is what the US Council of Muslim Organisations thinks. It's spearheading a drive to encourage Muslims to register, in an effort to stop Donald Trump, the Republican candidate, becoming President.

"We want the Muslim community to understand that if you give up your rights voluntarily, no one will come and give it back to you," said Osama Abu Irshaid, a member of the group's board. Imams and other Muslim leaders have been asked to encourage congregations to vote and a campaign has run since December throughout college campuses, bus stations and petrol stations in neighbourhoods with a high proportion of Muslims.

It began to combat an "unprecedented rise in Islamophobia," said Nihad Awad, executive director of the Council on American-Islamic Relations (CAIR). According to CAIR's database, 300,000 Muslims have registered to vote since November. The target is one million.

But they have opponents within the American-Islamic community.

Sajid Tarar, a businessman from Baltimore, has established a "Muslims for Trump" support group. In a move that surprised many core voters and GOP delegates, Tarar gave a speech and prayed for Trump on the main stage at the Republican National Convention this week.

Scores of delegates walked out and one man was told to be quiet when he heckled "no Islam!" during the speech.

Trump has far from ingratiated himself to America's Islamic community. One of the few outright policy suggestions the New York billionaire has announced is a "total and complete shutdown on Muslims entering the United States". And it is that suggestion which has helped him win such a groundswell of support among grassroot Republicans.

In a debate in December he said: "They're not coming to this country if I'm president. And if Obama has brought some to this country they are leaving, they're going, they're gone."

Last month he watered down the suggestion and said immigrants from countries "where there is a proven history of terrorism" would be blocked from entry. But he is still far from shy in his anti-Islam rhetoric.

However for Tarer, that is one of the reasons he supports Trump. Radical Islam "is not only a threat to Western civilisation, it's a threat to Islam itself," he said.

"ISIS, al Qaeda, Taliban, they have killed more Muslims than anything else, and that's a message Muslims need to hear and understand."

In an interview with Fusion, he said there was no contradiction for Muslims to support Trump. "The Quran says you need to be loyal to the country where you live," he said. "We have to do every possible thing to make our country safe." He has said he is not adverse to the surveillance of mosques, one of Trump's suggested policies, and supports a temporary ban on Muslim immigration.

He is not alone. According to a poll last month from CAIR, 11 per cent of American Muslims back Trump.

Michael Cohen is the co-chair of the National Diversity Coalition for Trump which aims to bring in minority support for the candidate. He said American Muslims were just as worried about terror in the US as other citizens.

He told Reuters Trump is "the only candidate who will enhance our national security, bring jobs back to America and fix our ailing economy".

In his speech to the GOP convention, Tarer said: "Let's pray to get our country back."

He added: "The values reflected by our leader must reflect the values of our forefathers.

"God bless America, God bless you, God bless Donald Trump."

If Tarer has his way, the most virilant anti-Islam candidate could be winning the support of millions of Muslims.