Washington indicated on Wednesday that it would stand by Israel as the Jewish state embarked on a wide military operation against Gaza in response to rocket attacks on the south, while other countries appealed for calm between the sides.

In a statement issued Wednesday, the US State Department strongly condemned Hamas, which it considers a terror organization, for shooting rockets at Israel, and placed itself firmly on the side of Israel in the latest round of fighting.

“There is no justification for the violence that Hamas and other terrorist organizations are employing against the people of Israel,” the statement read. “We call on those responsible to stop these cowardly acts immediately. We support Israel’s right to defend itself, and we encourage Israel to continue to take every effort to avoid civilian casualties.”

The State Department added that Hamas’s continued rule in Gaza was working to damage the Palestinian cause.

“Attacking Israel on a near daily basis does nothing to help Palestinians in Gaza or to move the Palestinian people any closer to achieving self determination,” the statement read.

Speaking briefly about an Israeli airstrike that killed Hamas military chief Ahmed Jabari earlier Wednesday, a Pentagon spokesperson said the US was “monitoring the situation closely.”

“We stand by our Israeli partners in their right to defend themselves against terrorism,” Lt. Col. Stephen Warren was quoted by AFP as saying.

Prime Minister Benjamin Netanyahu spoke with US President Barack Obama late Wednesday to update him on the situation and thank the White House for its support of Israel.

“The prime minister expressed his deep appreciation for US President Obama’s support of Israel’s right to defend itself,” the Prime Minister’s Office said in a release.

Obama and Netanyahu agreed that Hamas needs to stop its attacks on Israel to allow tensions to ease, the White House said. The two leaders agreed to stay in close touch in the coming days.

Obama spoke separately to Egyptian President Mohammed Morsi, given Egypt’s central role in preserving regional security, the White House said. The two men agreed on the need to de-escalate the conflict as quickly as possible.

On Wednesday, Israel began a large military operation, primarily from the air, against targets in Gaza, following three days of heavy rocket fire on the south of Israel. Netanyahu has indicated Operation Pillar of Defense may be “broadened” and Defense Minister Ehud Barak said the offensive would likely take time to knock out Gaza’s ability and willingness to attack Israel.

The IDF reported that Israeli Air Force planes had “damaged strategic targets of Hamas in a precise fashion” and “substantially damaged the launch capabilities of rockets from Gaza” at central and southern Israel.

Gazan terrorists responded by firing several dozen rockets at Israel.

The United Nations, France and England urged calm in the face of the escalating conflict.

UN Secretary General Ban Ki-moon spoke to Prime Minister Benjamin Netanyahu about the situation, which he described as “alarming.”

” [Ban] expressed his concern about the deteriorating situation in southern Israel and the Gaza Strip, which includes an alarming escalation of indiscriminate rocket fire from Gaza into Israel and the targeted killing by Israel of a Hamas military operative in Gaza,” a statement from his press office read. “The secretary general reiterated his strong condemnation of rocket fire out of Gaza and noted his expectation that Israeli reactions are measured so as not to provoke a new cycle of bloodshed that could cause additional civilian casualties and have dangerous spillover effects in the region.”

Ban also spoke with Morsi “about the worrisome escalation of violence in southern Israel and Gaza and the need to prevent any further deterioration,” a statement read.

The British foreign office wrote on Twitter that it was “aware of the reports” of Jabari’s death.

“We continue to call on all sides to exercise restraint to prevent a dangerous escalation that would be in no one’s interests,” the office said.

A French foreign ministry spokesperson also urged calm on both sides and said its consulate was in contact with the 6.000 French citizens living in the rocket zone of the south of Israel, according to a report in Maariv.

Much of the Arab world responded angrily to the military operation, with Egypt recalling its ambassador from Tel Aviv.

Netanyahu also spoke with US Vice President Joe Biden and European Union foreign policy chief Catherine Ashton, according to the PMO. The office did not elaborate on the content of the conversations but said that Netanyahu was planning further calls to world leaders in the near future.

Earlier in the evening, President Shimon Peres updated US President Barack Obama on the operation, saying that Israel would handle the fallout from the assassination “with great care.”

On Wednesday, Obama gave an hourlong press conference in Washington but did not mention the events in Gaza and the rocket fire on Israel’s south.

Times of Israel staff contributed to this report.