The army said forces crossed the border in southern Gaza and pushed more than half a mile (one kilometer) inside, and that troops had detained a number of Palestinians for questioning. The operation was limited in time, an army spokeswoman said, and the military had no plans to permanently capture territory inside Gaza.
The area is sparsely inhabited, and no major fighting was reported.
Palestinian security officials said Israeli troops took over and searched several houses, detained at least eight people, and used bulldozers to dig up land, apparently searching for tunnels. Militants have used underground tunnels in the past to attack Israeli positions.
The officials spoke on condition of anonymity because they were not authorized to speak to the press.
Recent days have seen a drop in Palestinian rocket fire, but four Israeli soldiers were wounded in a mortar attack on an army base near Gaza on Sunday. Militants from the Islamic Hamas group claimed responsibility for the strike. Hamas claimed responsibility for firing six more mortar shells at Israel on Monday, causing no casualties.
A truce in Gaza between Hamas and Israel unraveled last month when Hamas intensified rocket launches at Israeli towns, killing two Israeli civilians.
Israeli counterstrikes in Gaza have killed more than 60 Palestinians, most of them militants. Most of Israel's military operations so far have been from the air, but ground forces have begun making short incursions into Gaza as well.
On Monday, the Palestinian government approved a proposal for an overall truce among the rival Palestinian factions and between the Palestinians and Israel, Information Minister Mustafa Barghouti announced at a news conference in Ramallah.
But the cease-fire proposal Barghouti detailed included the West Bank — an idea Israel has consistently rejected as a ruse that would allow militants there to regroup and increase attacks.