For the second time in a week, rockets were fired into Israel from southern Lebanon in an apparent effort by Hamas to open a second front in the war:

There was no claim of responsibility for the rockets, which landed near the town of Kiryat Shemona. Hezbollah, the Iranian-backed guerrilla group that fought a monthlong war with Israel in 2006, had denied involvement in the earlier attack.

In Gaza, the Israeli military said its warplanes and helicopter gunships hit at least 60 targets early today, including more than 30 weapons-smuggling tunnels from Egypt.

A broad coalition of Israeli human-rights groups today decried the toll the fighting has taken on Gaza's civilians and suggested war crimes could be involved.

The fighting has weakened the military power of Hamas, and its political leadership is divided over plans for a possible cease-fire. But an Israeli intelligence official said Tuesday that the radical group remained dangerous, with 15,000 fighters, tunnels and a sophisticated arsenal of rockets and antitank weapons.

The senior official's assessment was delivered in a news briefing on a day when Israeli ground forces and Hamas militants battled in a neighborhood of high-rise apartments in southeastern Gaza City. Civilians fled as Israeli units, backed by shelling from warships near the seaside enclave, edged deeper into the city but appeared to stop short of Hamas strongholds.

The Israeli intelligence official, who spoke on customary condition of anonymity because of security concerns, did not underestimate Hamas but indicated that the group had been overwhelmed by 18 days of bombardment. The official said Hamas was not significantly tapping its caches of antitank and antiaircraft missiles but was occasionally using suicide bombers to spearhead combat missions.

"The level of damage to Hamas' military wing is less than the damage" to its civil infrastructure, the official said. "I think they will try to do their best to hit us, to come up with some symbolic achievement, a suicide operation or the kidnapping of an Israeli soldier."

Hamas officials have said the Islamic militant group's fighters are resilient and that its military wing is choosing when it will engage Israeli forces.

But the intelligence official said Israeli airstrikes had destroyed much of Hamas' rocket-launching capability. Two weeks ago, Hamas was firing about 80 missiles a day into southern Israel; the number has dropped to about 20 in recent days, On Tuesday the military said 18 rockets and mortars landed in Israel.