The Israeli government has decided to speed up the construction of its controversial West Bank barrier, according to security officials.
The barrier will cut off Jerusalem from the West Bank
Building work began over two years ago but only one third of the structure has been completed after a series of legal challenges to the route.
Palestinian negotiator Saeb Erekat said the order undermined efforts to revive the peace process.
Israel argues the barrier is necessary to prevent Palestinian suicide attacks.
Palestinians argue that the barrier is in reality a land grab that also cuts them off from their families, hospitals and schools.
The barrier is expected to be 425 miles long when complete and cuts deep into Palestinian territory in places.
"Jerusalem is a priority, and we hope that if the legal issues can be resolved, it will just be a matter of months to finish the fence and close off Jerusalem as we originally intended," said Giora Eiland, head of Israel's National Security Council.
Palestinian and international criticism and court rulings have forced Israel to revise the barrier's route and slowed construction, but it insists the project must be completed to protect its cities from suicide bombers.
The completion of the barrier around Jerusalem will create facts on the ground that prejudice any final settlement of the conflict in the region, Palestinians say.
The barrier will separate the West Bank from East Jerusalem, which Palestinians want as the capital of any future state.
"We urge the US to exert maximum efforts in order to have Israel Prime Minister Ariel Sharon comply with the cessation of violence and cessation of building the wall," said Mr Erekat.