The U.N. Security Council held closed-door consultations at the request of Russia, and Ambassador Vitaly Churkin later accused one country of foot-dragging, implying it was the U.S.
Germany's foreign minister was also headed to the region for talks with Israeli and Palestinian leaders. On Tuesday, Turkey's foreign minister and a delegation of Arab League foreign ministers were to visit Gaza.
Hamas, an offshoot of the region-wide Muslim Brotherhood, is negotiating from a stronger position than four years ago, when Israel launched a three-week war on the militants in Gaza. At that time, Hamas was internationally isolated; now, the Muslim Brotherhood is in power in Egypt and Tunisia, and Hamas is also getting political support from Qatar and Turkey.
President Barack Obama and other Western leaders have blamed Hamas for the latest outbreak of fighting, saying Israel has a right to defend itself against rocket attacks. However, they have also warned Israel against sending ground troops into Gaza, a move that would likely lead to a sharp increase in the Gaza death toll.
Over the years, Israeli governments have struggled to come up with an effective policy toward Hamas, which is deeply rooted in Gaza, a densely populated territory of 1.6 million.
Neither Israel's economic blockade of the territory nor bruising military strikes have cowed the Islamists, weakened their grip on Gaza or their ability to fire rockets at the Jewish state.
Instead, the two sides have observed informal cease-fires over the years, interrupted by flare-ups of violence.
Hamas has fired more than 1,000 rockets at Israel since the start of the latest offensive on Wednesday, kicked off by Israel's assassination of the Hamas military chief.
Of the 95 rockets fired Monday, 29 of them intercepted by Israel's U.S.-financed Iron Dome anti-missile battery, police spokesman Micky Rosenfeld said. Rockets landed in open areas of the southern cities of Beersheba, Ashdod and Ashkelon, and caused damage in a number of areas, including an empty school building in Ashkelon.
In Gaza, an Israeli airstrike on a high-rise building in Gaza City killed Ramez Harb, a senior figure in Islamic Jihad's military wing, the Al Quds Brigades, the group said. Israel said the target was a command center for the group. A number of foreign and local news organizations have offices in the building, which was also struck on Sunday. A passer-by, a carpenter from Gaza's tiny Christian community, was also killed, medics said.
And in central Gaza, four militants were killed in two separate strikes. In the air raid past midnight, Israeli aircraft struck the Islamic National Bank used to pay Hamas employees.
In the West Bank, Palestinian stone throwers protesting against Israel's Gaza campaign clashed with Israeli soldiers in several locations Monday. In the city of Hebron, a 22-year-old man was killed by army fire and three other protesters were injured, doctors said. The army said soldiers opened fire after a masked man approached them and failed to stop.
Associated Press writers Mohammed Daraghmeh and Dalia Nammari in Ramallah, West Bank, and Peter Spielmann at the United Nations contributed reporting.