JEFFREY BROWN: Egypt staged its first airstrikes into the Sinai Peninsula today since its 1973 war with Israel, but, this time, the targets were Islamic guerrillas.
We begin with a report from John Ray of Independent Television News.
JOHN RAY: The deadliest clashes in decades along a border upon which the peace of two nations and so much beyond depends.
Overnight, the Egyptian military moved in on militants blamed for a surge in violence that climaxed in a dramatic cross-border raid on Sunday. Gunmen had already killed 16 Egyptian guards before they commandeered this armored car. Only a missile from an Israeli aircraft brought them finally to a halt more than a mile inside Israeli territory.
Israel's prime minister called this a wakeup call for Egypt to root out radical groups taking up residence in the Sinai desert.
MIRI EISIN, former Israeli intelligence officer: We have felt for the last year-and-a-half that the Sinai region has become the Wild West. The Wild West may have been fun in the movies, but, in reality, you see what happens.
Different terrorist elements come in, they sit down, and they can use it because there's nobody there to stop them, and that's a direct threat for us.
JOHN RAY: Today, security forces on both sides of the border were on heightened alert.
The upsurge in violence along this border is a challenge to Israel, but it's an even bigger problem for Egypt's new Islamist government, a test of its ability and resolve to stick to security commitments that underpin the 30-year-old peace treaty between these two nations.
The deaths of the Egyptian border guards unleashed a wave of fury. Today, President Mohammed Morsi fired his intelligence chief. Israel believes he's passed an important test, but, among his supporters, there is much anti-Israel feeling. And the Egyptian army is limited by international agreement on the size of its presence in the Sinai.
So, one assault is unlikely to ease the tension or end the threat of violence.