Palestinians fired dozens of rockets into Israel from Gaza yesterday and an Israeli air strike killed a militant in a surge of violence after the emir of Qatar embraced the enclave's Hamas leadership with a visit.
Hamas claimed responsibility for some of the rocket and mortar attacks, raising questions among Israelis over whether it had been emboldened by the Qatari visit that challenged the Islamist group's diplomatic isolation.
Hamas had largely held its fire when other militant factions, including jihadi groups, launched cross-border rocket attacks in recent months.
For its part, Hamas accused Israel of stepping up its air strikes in the Gaza Strip to vent its anger over Sheikh Hamad bin Khalifa al-Thani's visit and pledged to "continue to hold a gun ... until Palestine is liberated".
Israel said it was "astounding" that Qatar, a US-allied Gulf state, would take sides in the Palestinian dispute and endorse Hamas, branded by the West as a terrorist group. Hamas seized the Gaza Strip in 2007 from fighters loyal to the Fatah faction of Western-backed Palestinian Authority President Mahmoud Abbas.
Some analysts saw the Qatari ruler's trip, the first by any national leader to Gaza since Hamas took over, as an attempt to build bridges between the group and the West and coax it into the peace camp amid Arab turmoil across the Middle East.
Previous rounds of cross-border attacks have usually run their course in days, with both Israel and Hamas seemingly aware of the risks of ramping up the conflict to full-scale warfare.
Israel's three-week-long invasion of the Gaza Strip, launched in 2008 with the declared aim of curbing rocket launchings, drew international criticism over a heavy Palestinian casualty toll in the territory of 1.7 million.
Though hostile to Israel, Hamas has mostly sought to avoid direct clashes as it shores up its rule in the face of more radical challengers and reaches out to potential allies abroad.
In a second day of violence, a Hamas militant was killed yesterday in an air strike Israel said was intended to stop rocket firings. On Tuesday, Israel killed three Hamas men, saying they had either launched attacks or were about to do so.
In southern Israel, three agricultural workers were wounded when a Palestinian rocket exploded near them.
A military spokeswoman said 72 projectiles were fired at Israel and that the Iron Dome system intercepted seven of them. Prime Minister Benjamin Netanyahu, who is seeking a renewed mandate in Israel's January 22 election, visited an Iron Dome anti-missile battery near the southern city of Ashkelon yesterday and threatened stronger action.
"We did not choose this escalation, nor did we initiate it, but if it continues we are prepared for a much wider and deeper operation," he said, pledging to press on with "targeted attacks" against militants preparing to fire rockets.
Israel kept schools shut in communities near the fenced Gaza boundary and residents were urged to remain indoors.
Both Israel and Hamas are thought to want to avoid an escalation into full-scale conflict. But if Israeli casualties resulted from rocket fire, Israel would be expected to engage in a more sustained assault than targeted assassinations.