Prime Minister Benjamin Netanyahu said on Tuesday that the main aim of a fence which Israel is building on its border with Egypt is now to block militants and not just smugglers and illegal migrants.
"Putting up the fence is first of all against terror activity, and only after that against (other) infiltrators," army radio quoted him as saying during a tour of the border.
Israel began constructing the fence late last year to stem the influx of thousands of illegal migrants through the porous border, which has also been a major drug and human trafficking route into Israel.
A statement from Netanyahu's office said work on the fence would be speeded up and was expected to be completed by next September.
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"Israel's border with Egypt is a border of peace. To continue the peace, there must be security, and to this end a fence is necessary," it quoted him as saying. "Its rapid construction is important for both peace and security."
Tensions between the two countries have risen since the killing last month of six Egyptian policemen on the border as Israel hunted militants who crossed from the Sinai and killed eight Israelis.
Last week, Egyptian crowds rampaged through the Israeli embassy in Cairo, with several of them tossing embassy papers from balconies and tearing down the Israeli flag.
It was the worst attack since Israel set up its mission in Egypt, the first Arab country to sign a peace treaty with the Jewish state, in 1979.
Nearly all of Israel's diplomatic staff were evacuated from Egypt after the attack on the embassy.