‘Price-tag’ tactics of West Bank Jewish settlers
With their hoodies, covered faces and cans of spray paint, they may in some ways look like average teenage vandals out for a night of trouble.
But on the streets of Arab East Jerusalem, some young Jewish people are up to more than just graffiti. They are part of what has become known as "price-tag gangs" and they are risking their safety to send a very political message.
Price-tagging is the term they use for a range of acts, from vandalism to arson attacks and religious desecration.
They carry out these crimes as an act of revenge. Primarily, they are warning their own government that there is a price to pay for any attempt to give what they believe is Jewish land to the Palestinians as part of the fragile peace process.
But they also say there is a price to pay by Arabs for attacks on Jews.
The price-tag gangs come from the hilltops of the West Bank, Arab territory that has been occupied by Israel since the war of 1967.
Israeli homes built on occupied land are illegal according to international law, though Israel disputes this. Israel regards the West Bank as territory whose final status is yet to be determined and has built 120 settlements here - around 300,000 Israelis now live in the West Bank, excluding East Jerusalem.
But there are also 100 small outposts scattered on strategic hilltops some of which are illegal under Israeli law because they are built on private Palestinian land.
The hills are the battle ground for the hilltop youth - price tagging is their calling card and they have sworn to sacrifice all to prevent this land being given to the Palestinians.
Moriah Goldberg is one of them. The 20-year-old was captured on CCTV in February in a Palestinian village.
She slashed open sacks of building materials, cars were sprayed with graffiti saying "revenge" and insulting the Prophet Muhammad.
Moriah, who is under house arrest in the ultra nationalist Israeli settlement of Tapuach, in the West Bank, did not deny her actions.
"A 'price tag' means that when the government of Israel decides to evict a settlement, an outpost, even the smallest wooden shack in the land of Israel - it has a price. Maybe it will make them think twice before they do it again."
The Israeli government's move to label some of the price-taggers' behaviour as acts of terrorism does not faze her.
"Faithless Jews who don't fear God can call me a terrorist if they want. I don't care what they say about me. I only care what God thinks. I act for him and him alone."
Graffiti is not the only hallmark of the price-tagger. There has been violence and intimidation: Arab cars have been hit by petrol bombs and people seriously injured. Security cameras caught the torching of trucks in Palestinian villages and - perhaps most worrying for the security situation - there have been arson attacks on mosques in the West Bank and Israel.
One of the most provocative price tags so far was in February in the Palestinian village of Burka, where the mosque was attacked, prayer mats were burnt, insults sprayed and war declared on the walls.
The Israeli authorities say they are determined to put an end to this and orders have gone out to the police and security services.
Mark Regev, spokesman for Israeli Prime Minster Benjamin Netanyahu, said the price-taggers would be stopped.
"If these extremists succeed - if you have, heaven forbid, a mosque or something goes up in smoke, this could promote extremism on their side and you could have a terrible impact. We've got to stamp these phenomena out."
Salam Fayyad, the Palestinian Authority's Prime Minister, is blunt in his assessment of their actions: "Certainly at least in some aspect of what those violent settlers commit - there's hardly any other way of describing it other than outright terrorism."
Israel's security forces are increasingly caught in the middle and the army has become a target of the hilltop youth as tensions rise.
One of the few price-taggers caught and successfully prosecuted is Alex Ostrovsky, 27, who was imprisoned for damaging vehicles in a military base. He is blunt in his view of his country's security forces and police who carry out the demolition of illegal outposts.
"If someone destroys my home I don't care if he's Arab or Jew. As far as I'm concerned he destroyed my house and therefore he's my enemy: a terrorist, a freedom fighter - depends where he is, who he's with. It's all the same thing. If calling me a terrorist helps me stay in my homeland, they can call me a terrorist."
Amid the price-tagging and tension over Jewish settlement in the occupied West Bank, peace talks with the Palestinians aimed at establishing two states side-by-side, are frozen.
For the Palestinians, the continuing growth of the settlements - 50,000 new residents in the last three years - remains the biggest stumbling block.
Salam Fayyad said the price-tagging and delays over moves to evict settlers from illegal outposts are taking a toll on the peace process.
"I see the viability of what remains of the two-state solution... giving way under the heavy weight of that settlement enterprise and associated violence."
For its part, Israel has formed a new taskforce to combat Jewish acts of extremism and says negotiating the future of the settlements will have to be part of the peace talks which they are ready to begin, without preconditions.
Regardless of what happens to the peace process the government knows it has to tackle the enemy within before Jewish militancy spirals out of control.
Panorama: Price Tag Wars, BBC One, Monday, 17 September at 20:30 BST and then available in the UK on the BBC iPlayer.