Reporting from Jerusalem — Two Israeli soldiers and two Palestinian militants were killed Friday in a gun battle in the Gaza Strip, heightening fears that violence in the region is returning to levels not seen for more than a year.
The clash followed a recent uptick in Palestinian rocket attacks against southern Israeli cities and towns, including one last week that killed a Thai farmworker.
The fighting Friday caused Israel's first military deaths in Gaza since January 2009, shortly after it concluded a 22-day assault against Hamas, the militant group that controls the seaside enclave.
"This is a tragic and painful incident for us," Israel Defense Forces spokeswoman Avital Leibowitz said. "In southern Israel we feel there is an everyday war."
Israeli officials vowed a strong retaliation, saying they were considering military operations inside and around the border of the strip. About five Israeli tanks moved across the border Friday night, Palestinian sources said.
In late December 2008, Israel invaded Gaza, from which it had unilaterally withdrawn in 2005, and launched a three-week campaign to stop rocket attacks on Israel. The operation led to the deaths of about 1,400 Palestinians and 13 Israelis.
Leibowitz said military officials believed their response to recent Palestinian rocket attacks had been too moderate.
"The other side might be interpreting our reaction as a weakness," she said. "But we will not tolerate it. If Israel is on fire, the other side will be on fire as well."
Hamas leaders blamed Israel for Friday's clash, saying that a large number of Israeli soldiers, supported by Apache helicopters, provoked its security forces by crossing 500 yards into Gaza. A Hamas spokesman accused Israel of attempting to stir up violence to divert attention from the failed peace process and recent international pressure over its housing construction plans in Jerusalem.
Gaza's borders cannot be crossed "without a price, and today's [Israeli] elite paid a heavy price by our fighters," said Abu Obeida, spokesman for the Hamas military wing, the Izzidin al-Qassam Brigade.
"We will not stand silent in front of these crimes and the daily incursions in our land."
Israeli officials said its soldiers must cross into Gaza on occasion to secure the border. They said soldiers Friday were investigating what they believed was an attempt by three Palestinians to plant explosive devices. As the soldiers approached, the Palestinian fighters opened fire and soldiers returned fire, Leibowitz said.
Special correspondent Rushdi abu Alouf in Gaza City contributed to this report.