Unidentified gunmen crossed into Israel from Egypt's Sinai desert early Monday and killed a construction worker before Israeli troops returned fire and killed two of the attackers.

Israel's military says the gunmen ambushed two vehicles carrying workers involved in building a fence along the border. It said the assailants detonated a roadside bomb and opened fire with anti-tank rockets and rifles, killing an Israeli Arab man and wounding two other workers.

Israeli troops responding to the attack killed two assailants and searched for additional infiltrators but did not find any. An Israeli defense official said the troops' quick response to the cross-border raid prevented “more serious consequences.”

In a separate incident, the Israeli military carried out an airstrike in northern Gaza Monday, killing two Palestinians whom it accused of cross-border sniper attacks on Israeli civilians. Palestinians said the men were riding a motorcycle and identified them as members of the militant group Islamic Jihad.

Israeli Defense Minister Ehud Barak said the ambush on the Egypt border reflected a “disturbing deterioration” of Egyptian control in the Sinai peninsula. Militants have become increasingly active in the territory since former president Hosni Mubarak was ousted in an uprising last year.

Barak said Israel expects whoever wins Egypt's presidential election to uphold the two neighbors' peace treaty, take responsibility for security arrangements in Sinai and stop cross-border attacks.

The border had been quiet for decades until last August, when militants infiltrated into southern Israel and killed eight civilians on a desert highway. Israeli troops inadvertently killed several Egyptian security personnel while in pursuit of the attackers.

Since August, Israel has been building a stronger barrier along its 230-kilometer border with Sinai to try to prevent further raids and to stop a wave of illegal African migration to the country.