Israeli troops rolled out barricades of concrete blocks and spiked metal strips across the West Bank yesterday, opening battle with the Palestinians for control of vital roadways.

A day after four Jews were killed in drive-by shootings, Israel fears its high-security routes could become a killing zone for troops and Jewish settlers in the West Bank and Gaza. Israel's deputy prime minister, Binyamin Ben Eliezer, called it the Palestinians' "death-by-road" campaign yesterday.

New barricades were erected or fortified throughout the West Bank, squeezing shut the ring of steel imposed on Palestinian towns since the conflict began seven weeks ago.

Israel's army chief, Shaul Mofaz, admitted yesterday that the West Bank could not be hermetically sealed. Instead, the closure is designed to cripple the Palestinian economy, and there could be further pain if the army acts on a proposal for a partial curfew on cars with Palestinian number plates.

Four Palestinians were shot dead by Israeli soldiers yesterday, an almost routine casualty rate during these weeks of bloodshed. But today could bring a steep rise in violence.

The Palestinians are poised to confront the closure after Yasser Arafat's Fatah organisation urged the people to throw Israeli soldiers and settlers out of the West Bank on the 12th anniversary of a symbolic declaration of independence.

"Fatah calls on the people to prevent the occupation forces and the herds of settlers from entering Palestinian areas," a statement, published yesterday in Palestinian newspapers, said. "The day will be a day of challenge between the will of the people and the will of the heavily armed occupation."

In Neguhot, a hardline settlement west of Hebron hunkered down with Israeli soldiers behind barbed wire and electric yellow gates, 13 Jewish families have been penned in by local Palestinian hostility for months.

Earlier this year, a two-and-a-half mile stretch of the main road to the settlement was transferred to full Palestinian control, under the now comatose peace process. When the violence erupted seven weeks ago, the road, already a risky route for the settlers because of sporadic stone-throwing, became off limits.

From this hilltop at 770 metres, the settlers can see the twinkling lights of Tel Aviv. But if they want to travel to the nearest Jewish settlements a few miles away, they must follow a circuitous route that takes nearly two hours.

"The problem with the road is that the army does not rule there. It is in Palestinian hands, and the army says if we pass through there we could get shot," said Neguhot's secretary, Yigael Leibner.

A former army lieutenant, Mr Leibner was one of the founding settlers of Neguhot some three years ago, and he fervently believes the outposts manned by some 200,000 Jews in the West Bank and Gaza are vital to Israel's interests. "Where there are settlements, there is security," he said. "The army puts more into it, and the settlers help keep the roads going."

That is not how they are seen by the Palestinians, who consider the settlements a symbol of the occupation; nor is that the interpretation from Israeli liberals, who believe they remain the greatest obstacle to peace. On Monday, the Israeli movement, Peace Now, launched a high-profile campaign, calling on the prime minister, Ehud Barak, to stop the expansion of West Bank settlements.

"The building of settlements and the opening of roads leading to them is a provocative act calling unnecessarily for counter-violence," Peace Now said.

Many settlers see their presence in the West Bank as a biblical birthright; those who oppose them have drifted from the true Zionist mission.

Mr Leibner believes that the Palestinians should go - and their emigration be encouraged - and that the settlers should tough it out.

"Every Arab attack should be answered by a new Jewish settlement coming up, another Jewish house, and another Jewish kid," he said. "I do not think we can win this fight. The long-range solution is not the army, it is to put our feet deeper into the land."