"Shame on you Obama, Osama is still inside us," was the rhythmic chant of a small group of protesters in Gaza City this week.
Most of them were young men in their 20s. They were small in number, not much more than 50, but strong in voice.
"We came here to show our anger at the murder of Sheikh Osama Bin Laden," said Jihad, a stout man with a thick beard in Islamic traditional dress. He's a Salafist jihadi.
"The Salafist jihadis in Gaza yearn to have acceptance from al-Qaeda," says Nathan Thrall, a Middle East Analyst at the International Crisis Group and an expert on radical Islam in Gaza.
"They are not yet affiliates of al-Qaeda but to say they are inspired by al-Qaeda is accurate," says Mr Thrall.
Salafists practice a very conservative and traditional form of Islam. They take their inspiration from the early generations of Muslims who were close to the Prophet Muhammad and his message.
In Gaza the vast majority are non-violent. Salafist jihadis espouse violence.
They are a tiny minority in Gaza. Nathan Thrall says Hamas officials estimate their numbers to be in the tens rather than the hundreds.
They have often been in conflict with the Hamas government in Gaza, which they regard as too moderate and too willing to compromise Islamic principles.
And the Salafist voice is being heard.
Earlier this month, a day after the killing of Osama Bin Laden in Pakistan, the Hamas Prime Minister in Gaza Ismail Haniyeh condemned the American operation. Mr Haniyeh called Bin Laden an "Arab and Muslim holy warrior".
Such words were ill-timed for those who hope the recent Palestinian unity deal between Hamas and its secular rivals Fatah might see Hamas moderate its views.
Hamas has since rowed back on the comments, but many believe Mr Haniyeh at least partly had the Salafist constituency in Gaza in mind when he made the remarks.
"The threat posed by the Salafists to Hamas is really an ideological one," says Nathan Thrall.
"It's very difficult for Hamas to defend itself against Islamist challengers who say it is failing to impose Islamic law, fight Israel and liberate the Palestinian people."
But he says the physical threat that the Salafists pose to Hamas is much smaller.
"Hamas has shown in the past that it is able to crush the Salafist jihadis when they cross red lines."
One such red line was the kidnapping and murder of Vittorio Arrigoni by a small Salafist group in Gaza in April.
The Italian pro-Palestinian activist, who was living in Gaza City, was abducted and strangled.
Before he was killed a video showing the 36-year-old beaten and blindfolded was posted - on a Salafist website.
The kidnappers demanded the release of Salafist prisoners being held in Hamas jails.
'Closing the file'
Hamas had largely been credited with reducing the threat of kidnapping in Gaza and Mr Arrigoni's murder was seen as a challenge to its authority. It hit back with force.
A few days after the killing Hamas security forces surrounded a house in central Gaza where the three alleged Salafist kidnappers were holding out.
After a fierce gun battle, two of the Salafists ended up dead. One was captured. It's believed since then a number of other Salafists have been arrested across Gaza.
"I think we succeeded now to end this file," Hamas's Deputy Foreign Minister Ghazi Hamed told me.
"This was a small group. Some of them were killed. Some of them were arrested. Everything is under control."
It emerged this week though that an American citizen living in Gaza was advised by Hamas to leave the strip because of threats from Salafist groups and a possible kidnapping plot to avenge the death of Osama Bin Laden.
Depending on which way you look at it, the news was either proof that Hamas is one step ahead of the Salafists and is indeed in control of Gaza, or that the Salafist threat is greater than Hamas perhaps likes to make out.
Government and 'resistance'
Hamas does have the means to largely control Gaza. Tens of thousands of people work in the security forces here.
Just a few weeks after Mr Arrigoni's murder Hamas managed to successfully police the first ever Gaza Marathon, a potentially easy target for Salafist jihadis.
Thousands of Hamas police lined the route, which covered Gaza from top to bottom. The event allowed Hamas to show it was in full control.
The military face of Hamas is a familiar one. It sells itself on being a movement of fighters against Israel's occupation. But it also has to govern. That means schools, hospitals and keeping the streets clean.
Maher Sabra, an analyst at al-Ummah University in Gaza, says this has presented Hamas with a challenge.
"It is very difficult to combine the two things, to be in power as a government taking care of people and at the same time working as a resistance movement."
For the past four years, Mr Sabra believes, Hamas has had to become more pragmatic.
"They are in a delicate position. But so far they are surviving," he smiles.
For the small number of Salafist jihadis, though, Hamas has got the balance wrong.
Some Salafists are disgruntled former Hamas members who believe the movement is neglecting its principles.
The fact that a number of Salafists were once linked to Hamas has led some in Israel to accuse the media of playing up the Hamas-Salafist split, suggesting the two are actually closer than is sometimes made out.
But Nathan Thrall from the International Crisis Group rejects this and says the conflict is real.
"Hamas has very little interest in having Islamist challengers question its credentials."
Salafist jihadis are a tiny minority in Gaza. But as the dynamics of Palestinian politics shift in the coming months they maintain a limited potential to make themselves heard, either by launching rocket attacks on Israel to break the relative calm or by trying to challenge Hamas more directly.