GAZA CITY, Gaza Strip — The top leader of Hamas dared Israel on Monday to launch a ground invasion of Gaza and dismissed diplomatic efforts to broker a cease-fire in the six-day-old conflict, as the Israeli military countered Gazan rockets with a new wave of deadly airstrikes on the Palestinian enclave.
The airstrikes have killed more than 100 Palestinians since they began Wednesday. Monday’s strikes included a second hit on a 15-story Gaza City building that houses media outlets, in which a top militant leader was killed. Among the volley of rockets fired from Gaza into southern Israel on Monday was one that hit a vacant school.
Speaking at a news conference in Cairo, where the diplomatic efforts were underway, the Hamas leader, Khaled Meshal, suggested that the Israeli infantry mobilization on the border with Gaza was a bluff on the part of Prime Minister Benjamin Netanyahu of Israel.
‘‘If you wanted to launch it, you would have done it,’’ Meshal told reporters. He accused Israel of using the invasion threat as an attempt to ‘‘dictate its own terms and force us into silence.’’
Rejecting Israel’s contention that Hamas had precipitated the conflict, Meshal said the burden was on the Israelis. ‘‘The demand of the people of Gaza is meeting their legitimate demands — for Israel to be restrained from its aggression, assassinations, and invasions, and for the siege over Gaza to be ended,’’ he said.
International leaders stepped up efforts to broker a cease-fire. United Nations Secretary General Ban Ki-moon traveled to Cairo to make a personal appeal for an end to the violence.
Hamas and Israeli negotiators appeared far apart as the cease-fire talks continued, including disagreement over Hamas’s demands that the Gaza blockade be lifted. Both sides said they remained open to a diplomatic solution, but were prepared for further fighting.
President Obama’s administration worked behind the scenes to end the fighting, asking Arab and European allies to help persuade Palestinian militant groups to stop firing rockets. During his diplomatic tour of Asia, Obama called Netanyahu and President Mohammad Morsi of Egypt to discuss ways to halt the violence.
The Palestinian group Islamic Jihad sent a text message to reporters saying that one of its leaders, Ramez Harb, was killed Monday in the second Israeli strike on the media center in Gaza City, the Associated Press reported. Harb was a leading figure in the group’s militant wing, the Al Quds Brigades.
The Hamas Health Ministry said Monday evening that a total of 107 people had been killed since Wednesday morning, when Israeli airstrikes began, after months of Palestinian rocket fire into Israel. A spokeswoman for the Israeli military said she believed that a majority of these were militants, though it is difficult to know because Hamas’s own fighting brigade and the other factional groups are secretive.
The Hamas ministry said the dead included at least 26 children, 10 women, and 12 men older than 50, who were presumably not involved in combat. Of the remainder, at least 36 are known militants. Hamas officials said more than 860 have been wounded, 260 of them children.
Three people have been killed so far in Israel — all civilians — in a rocket strike that hit an apartment house in the southern Israeli town of Kiryat Malachi on Thursday morning. The Israelis have said at least 79 Israelis have been wounded and that Gaza rockets have reached as far north as Tel Aviv.
The latest Gaza casualties — 22 people reported killed since midnight local time — included Palestinians killed in strikes by warplanes, a drone attack on two men on a motorcycle, and a father and two toddler sons in their bombed northern Gaza home, witnesses and medical sources said.
On Tuesday, Israeli aircraft battered the headquarters of the Gaza Strip bank the territory’s Hamas rulers set up to sidestep international sanctions.
The inside of the bank was destroyed, and a building supply business in the basement was damaged.
On Sunday, Israeli forces attacked two buildings housing local broadcasters and production companies used by foreign outlets.
Israeli officials denied targeting journalists, but on Monday Israeli forces again blasted the Al Sharouk block, a multiuse building where many local broadcasters, as well as Sky News of Britain and the channel Al Arabiya, had offices.
Israel says its onslaught is designed to stop Hamas from launching the rockets, but, after an apparent lull overnight, more missiles hurtled toward targets in Israel, some of them intercepted by Israel’s Iron Dome defense system.
Of five rockets fired on Monday at the southern Israeli city of Ashkelon, four were intercepted but one smashed through the roof at the entrance to an empty school. There were no reports of casualties. Other rockets rained on areas along the border with Gaza. Later a second salvo struck Ashkelon. Several rockets were intercepted, but one crashed down onto a house, causing damage but no casualties.
Israeli officials said 135 rockets were fired from Gaza at Israel on Monday, of which 42 were intercepted by Iron Dome. Most of the others landed in open areas.
In a statement Monday, the Israel Defense Forces said overnight targets included ‘‘underground rocket launchers, terror tunnels, training bases, Hamas command posts, and weapon storage facilities.’’ But news reports said the strikes flattened two houses belonging to a single family, killing two children and two adults and injuring 42 people, while a shrapnel burst from another attack killed one child and wounded others living near the rubble of the former national security compound.