Both sides can be satisfied: Israel prevented a border breach, while Hamas showed off its power to rally the people of Gaza.
Army reminds Gaza residents not to attempt to cross the fence.
Israel claims the move is a necessary security measure given regular clashes in nearby Palestinian refugee camp.
Trump sparked outrage in Mexico with his campaign vow to build a wall along the southern US border to keep out illegal immigrants and drugs, and to make Mexico pay for the construction.
The planned 42 kilometers represents just a fraction of the 320 kilometers in "gaps" in the West Bank security barrier.
The plan, revealed on Thursday, will cost an estimated $568 million less than previously estimated, according to the report.
"What good is a fence if it can be climbed over or climbed under?" opposition leader asks after woman murdered in Beit Horon settlement.
The new fence will run from the border east of Eilat to the Timna airport, and will be built entirely on Israeli land.
A perfect storm is brewing for Israel. After years of counterproductive concessions, if the Jews wish to preserve their sovereignty, what is required is ruthless resolve, not reticent restraint.