Two Israeli tourists and their Egyptian guide were killed Sunday when a gunman opened fire on them and a group of travelers in Egypt, according to the Israeli Foreign Ministry.

The attack unfolded in Alexandria and was allegedly committed by a local resident, the Foreign Ministry said. The tour guide was an Egyptian, according to the Foreign Ministry.

The shooting left at least one other Israeli tourist injured, the Foreign Ministry said.

Israeli officials -- including the Israeli Embassy in Cairo, the Prime Minister's Office and the Israel Defense Forces -- are working with Egyptian authorities to return the slain Israeli citizens to Israel as soon as possible, the Foreign Ministry said.

-ABC News' Becky Perlow

More than 500 people have been killed in Israel and another 2,000 injured as rocket attacks and fighting continued between Israeli forces and Hamas militants, the Israeli Health Ministry said Sunday.

At least 30 Israeli police officers have been killed in the fighting, mainly in Sderot, where Hamas gunmen took control of the police station.

Meanwhile, fighting is still ongoing in six places, including Sderot -- which sits just two miles from the border with Gaza -- even after the police headquarters standoff ended and a rocket injured four people on Sunday morning.

On Saturday, graphic video showed dozens of dead bodies, bullet ridden homes and vehicles following an assault by armed militants.

Israel has also opened a hotline for family members who can come forward to give DNA samples to help identify those who have died.

Early Sunday morning, Israel police said in a statement, "The first phase ends in these hours by the destruction of the majority of the enemy forces that penetrated our territory. At the same time we started the offensive formation and it will continue without reservation and without respite until the objectives are achieved."

Israeli police announced the cabinet decided the supply of electricity, fuel and goods to the Gaza Strip will be suspended.

"We will restore security to the citizens of Israel and we will win," Israeli police said.

In remarks with Israeli Prime Minister Benjamin Netanyahu, Secretary of State Antony Blinken said at least 25 Americans had now been confirmed dead in Israel.

Netanyahu described some of the atrocities committed by Hamas.

"Hamas has shown itself to be an enemy of civilization: The massacring of young people in an outdoor music festival, the butchering of entire families, the murder of parents in front of their children and the murder of children in front of their parents. The burning of people alive, the beheadings," he said.

"Hamas should be treated exactly the way ISIS was treated," he said. "They shouldn't be spit out from the community of nations. No leader should meet them. No country should harbor them. And those that do should be sanctioned."

Blinken said he was speaking not only as an American diplomat, but as a Jew, a husband and a father of young children, saying it was impossible for him to look at photos of families killed "and not think of my own children."

"The same time that we've been shocked by the depravity of Hamas, we've also been inspired by the bravery of Israel citizens," he said. "The grandfather who drove over an hour to a kibbutz under siege, armed only with a pistol and rescued his kids and grandkids. The mother who died shielding her teenage son with her body, giving her life to save his -- giving him life for a second time."

Blinken remarked that some U.S. aid had already been delivered, and that more military aid was on his way. He said the administration would work with Congress to meet Israel’s additional needs and that bipartisan support for Israel was "overwhelming."

The secretary called on world leaders to condemn Hamas.

Blinken also reiterated that Israel "has the right -- indeed, the obligation -- to defend itself" but that it was "so important to take every possible precaution to avoid harming civilians."

-ABC News' Shannon Crawford