camp excitedly mobbed the armed, olive-uniformed officers from the second special brigade of the National Security force, deployed with their soft-top Jeeps across the road for the first time. They crowded round the blue and white patrol car driven by Major Eyad Shteyer, the city's deputy police chief, thrusting their hands through an open window in friendly greeting.

The welcome for the sudden and comprehensive visibility of the forces of law and order in Nablus – a city widely seen as the most lawless in the West Bank over the past two years – was clearly spontaneous.

"This is very good," said Ahmed Salam, 14. "There have been a lot of stolen cars and masked people have been kidnapping grown-ups."

By yesterday the 300-strong, specially trained, National Security force deployed on Friday were setting up checkpoints on the busy main roads across much of the city. Their arrival coincided with the symbolically important first visit to Nablus since June of Salam Fayad, the man behind the deployment.

It is highly unlikely that the deployment will soon persuade Israel to halt its near-nightly raids in pursuit of armed militants or hand back ultimate control of the city to the Palestinian Authority. The National Security force is only allowed by Israel to deploy from 6am to midnight and Major Shteyer claims that after the deployment, Israeli military vehicles approached the police station in the middle of the night, unleashing tear gas, smoke and sonic bombs to "give us a message that they are still here."

But the new commitment to curbing crime appears to have reversed a rapid decline in the faith of residents that Mr Fayad and President Mahmoud Abbas were prepared to make the streets safer.

On a city tour, Major Shteyer, while welcoming the National Security deployment, repeatedly points to the evidence that his force's own recent crackdown on crime predates their arrival. In the Rafidia neighbourhood, he shows some 230 mangled, half-crushed stolen cars – many, he says, handed to Palestinian racketeers by their Israeli owners as part of a long-standing insurance scam – which the police seized in the past two months.

The illegal stalls in the city centre which created traffic anarchy have all been forcibly removed.

The owner of a sweetshop, Kessem Majeed, 43, said: "Security has got much better in the last two or three weeks. Before, my neighbours' shops were robbed, we saw gangsters in the streets and sometimes there was shooting. No one did anything but now if you call the police they will be here in five minutes."

But the security forces' writ – other than by agreement with the militias – does not run deep in the Nablus casbah, site of frequent gun battles between militants and Israeli forces:

Major Shtayer says what he sees as the armed resistance cannot be disarmed while Israel continues its raids; Israel says it will not stop the raids until the Palestinians can guarantee security.

Nasser Harraz, a spokesman for the Al Aqsa Martyrs Brigade, who is wanted by Israel, says those in the group not covered by a recent amnesty of wanted men have forsaken violence in Israel itself – or indeed outside Nablus – but insists that the Brigades will not give up weapons until the occupation ends. He said: "Our target is well known – to defend our people."

Major Shteyer says that if the Israeli military withdrew from Nablus, he could ensure the disarmament of such armed groups within 48 hours.

He said: "This is very sensitive. We do not accept being partners of Israel in what they doing in areas in the control of the Palestinian Authority."