Prime Minister Binyamin Netanyahu consulted by telephone with US President Barack Obama on Friday evening over the Israeli military operation in the Gaza Strip and the continuing Palestinian rocket fire.During the conversation, rocket sirens sounded. Netanyahu told Obama that millions of Israeli civilians were being forced to endure the sirens.Netanyahu told Obama that Hamas was responsible for the harm done to Palestinian civilians in Gaza who are being used as human shields. The premier mentioned UNRWA's acknowledgement that Hamas had hid rockets underneath one of the UN agency's schools in Gaza.The prime minister thanked Obama for Washington's support for Israel's right to defend itself as well as American backing for the Iron Dome project.Obama on Friday said he spoke to Netanyahu about the situation in Gaza, underscoring the US support for Israel to defend itself but raising concerns about consequences of wider conflict.Obama said he reaffirmed the United States' strong support for its ally but that he "also made clear the United States ... and our allies are deeply concerned about the risks of further escalation and the loss of more innocent life.""We are hopeful that Israel will continue to approach this process in a way that minimizes civilian casualties," Obama told reporters at the White House.Obama also said he told Netanyahu that US Secretary of State John Kerry is also prepared to visit the region. "All of us are working hard to return to the cease-fire that was reached in November of 2012," Obama said.Netanyahu was scheduled to hold a number of telephone conversations with world leaders Friday to shore up international legitimacy for the Gaza operation and ensure “room to maneuver.”Earlier in the day, at an emergency cabinet meeting, the ministers unanimously approved the security cabinet decision that authorized the ground operation.The ministers were briefed on the situation by Chief of Staff Lt.-Gen Benny Gantz and Defense Minister Moshe Ya'alon. The minsters were told that the IDF is prepared to expand the operation, and the IDF will be given the time to carry it out.Diplomatic officials said that Israel will formally ask the UN to publish pictures of the missiles that on Thursday were found in an UNRWA school. This will help show the world that Hamas uses its schools to fire rockets on Israeli ones.Netanyahu will in the coming hours update the opposition leaders on the Gaza operation.The officials said there was currently no concrete cease-fire proposal on the table that Israel was dealing with. German Chancellor Angela Merkel earlier Friday said that she supported Israel’s right to defend itself.“Of course, this needs to be done in a reasonable manner,” Merkel told reporters in Berlin. “Every country must defend itself when it is attacked [the way Israel is being attacked by Palestinian rockets].”The chancellor said that she still believes that both sides can reach the cease-fire agreement proposed by Egypt. “We hope that the Arab initiative will find unconditional agreement among the Arab countries and parties,” she said. “We, the government of Germany, still believe that there needs to be a two-state solution,” Merkel said.