TEL AVIV — Israel has built fences on its frontiers with Lebanon, Syria and Egypt. It has constructed barriers through parts of the occupied West Bank and along the border with Gaza.

Now the Israelis are moving ahead with a fence along at least part of their border with Jordan as well.

On Monday, the office of Prime Minister Benjamin Netanyahu announced that Israel would begin work on an 18.6-mile stretch of fence along its eastern border with Jordan — a friendly neighbor, unlike Lebanon and Syria — but in the view of Israeli security officials, a possible source of illegal immigrants and hostile infiltrators.

News of the fence construction coincided with attacks on Israelis in the occupied West Bank, underscoring the frequent episodes of violence that have heightened security concerns.