A plan to construct a 100 km security fence along part of the western border of the West Bank has been approved by Israeli Prime Minister Ariel Sharon.

The fence is seen as a key part of recently proposed Israeli plans to build security 'buffer zones' around Palestinian areas.

The first part will extend for 110 km (68 miles) between Kafr Salam and Kafr Qasim along the western edge of the West Bank, the Israeli newspaper Ha'aretz reported.

Israeli Government spokesman Ranaan Gissin said work on the fence had already begun.

The concept of buffer zones is not new - but the plans have been revived amid recent violence in the West Bank and a series of Palestinian suicide bomb attacks on Israeli targets.

The scheme is seen by some analysts as a 'second phase' to Israel's military operation in the West Bank in April.

Defence plan

Precise details have yet to be drawn up, but an Israeli Government spokesman told BBC News Online that the scheme could incorporate elements of the 1968 Allon plan.

Ariel Sharon is backing the buffer zone

Although never officially proposed, the plan drawn up by then Israeli Foreign Minister Yigal Allon, defined security requirements along Israel's eastern border.

It set out a 10km-wide buffer zone running along the Jordan valley, designed to protect Israel from a possible attack from the east.

Under any new plan, a 5km zone patrolled by Israeli Defence Force (IDF) soldiers, would be set up around the remainder of the border with Israel-proper.

The government spokesman told BBC News Online that any security zone would follow the boundary of the existing green line boundary.

Fortification of the border area has been under way for months. Many stretches are already heavily fortified, with high walls or fences and video surveillance cameras.

'Borders redrawn'

Critics have condemned previous plans for security zones on the grounds that Israel's borders would be effectively redrawn.

IDF troops would patrol the buffer zone

Others within the Israeli Government are reluctant to create what would effectively be a political border between Israel-proper and the West Bank.

Analysts say that while such zones might seal off Israelis in other part of the country from Palestinians, 140 Israeli settlements within the West Bank would remain vulnerable.

A population of 400,000 Palestinians living in dozens of villages within the buffer zone would also fall under permanent Israeli control.