Black flags have been removed from rooftops. Graffiti proclaiming the extremists' imminent victory has been whitewashed.

“What happened in Syria has made our hearts bleed, it made me forget myself, my family and all that I own in this life. So I went for Jihad for the sake of Allah, and to make Allah's word supreme, and to help and support our brothers in Syria, a former terrorist claimed.

But supporters of the Middle East's most radical extremist group are only laying low after their surprise show of strength in protests last summer.

Despite government efforts, ISIS activists say support for the group is growing in Maan and elsewhere in Jordan.

"I joined the Jihad in Syria in 2013 with the Nusra Front to make God's religion victorious and to raise the flag of 'No God, but God' (jihadist flag). I fought against the regime forces during the time I was in Syria, but I returned (to Jordan) because of illness, Omar Mansour, former terrorist from Maan said.

"Yes, people are divided in general, but after the campaign (US-led coalition campaign against the Islamic State group) more people have become supporters of the ISIS group. I think that in the future the Nusra Front will be exclusively for Syrians only,” Mohammed al-Shalabi, known as Abu Sayyaf, preacher of “jihadi Salafism” said.

Jordan is one of the West's key allies in the region. Over the summer, jihadi Salafi marches were held in Maan, Zarqa and several other cities, with protesters raising black banners and chanting slogans in support of the ISIS group.

Given the poverty and anger at perceived government neglect, such protests could easily erupt again and spread, warned Maan's mayor, Majed al-Sharari.

"If this situation continues. I think a catastrophe will occur in Jordan. I think it will not take long, I think it will start in 2015." Majed al-Sharari, Mayor of Maan said.

Up to two-thousand Jordanians are fighting in rebel ranks in Syria and Iraq, most of them with extremist factions, and several hundred have been killed, according to Hassan Abu Haniyeh, an expert on Islamic movements.

One of the leading ISIS group activists in Maan said he and others are still working to build their base.

"There is a huge exaggeration of the phenomena of extremism in Jordan. We do have a small group of Jordanians who express their sympathy for terrorism, and terrorist organisations, and fundamentalist ideology, but we think this phenomena is under control," Mohammad al-Momani, State Minister for Media Affairs said.

That may be overconfidence. Hardcore supporters of the ISIS group's self-proclaimed "caliphate" likely number in the thousands in a nation of 6.5 million.

"There are deep problems in Jordan, basically with the nature of economic problems, as well as political and social issues, if the problems are not solved, more hotbeds for this organisation (ISIS group) will be created. The number joining the organisation is growing, for example before the beginning of the Arab Spring the numbers of jihadis didn't exceed four-thousand, now we are talking about nine-thousand." Hassan Abu Haniyeh, expert on Islamic movements said.

The government says the threat is overblown. But extremists do have momentum, attracting followers with promises of radical change and an ostensibly more just society at a time when many Jordanians can't find jobs, struggle with rising prices or feel abandoned by the pro-Western ruling elite.

The war in Syria gives them a cause and battlefield experience. Support for the ISIS group runs strongest among "jihadi Salafis".

The "jihadi Salafi" movement backs the waging of violence - holy war, as they portray it - to bring about rule by the strict version of Islamic Shariah law that they contend is the only acceptable interpretation.

Experts estimate that the number of Jordan's "jihadi Salafis" has doubled since the 2011 outbreak of the Arab Spring uprisings, to at least nine-thousand hardcore members.

They are part of the broader movement of Salafis, who number in the tens of thousands around Jordan.

The vast majority in the movement opposes the "jihadi" branch and say preaching, not violence, is the way to spread their vision of Islam.