The number of Israeli military roadblocks in the West Bank increased by nearly 40 percent in the past year, a UN aid agency said Wednesday.

The placement of these checkpoints and unmanned physical obstacles means the West Bank is increasingly being carved up into separate parts, with travel between them becoming more and more difficult, said David Shearer, head of the UN's Office for the Coordination of Humanitarian Affairs (OCHA) in Jerusalem.

In all, there were 528 checkpoints and obstacles in the West Bank, up from 376 in August 2005, Shearer said, presenting new statistics.

"We are seeing a continuing closing down, locking down of Palestinian areas," Shearer said, noting that tight travel restrictions were also in place during the height of the intifada, between 2000-2003, when dozens of suicide bombers carried out attacks in Israel.

"Since then it's become much more systematic, much more sophisticated in terms of monitoring Palestinian movement and closing Palestinian movement," he said. "The West Bank, for example, is effectively being chopped up into three big areas... and there are pockets within those areas where people also can't move."

Captain Adam Avidan, spokesman for the Civil Administration, said that Israel tries "as much as possible to preserve the Palestinians' way of life and to avoid hurting civilians in its war on terror."