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.

Hamas fighters are believed to be "still hiding" in some communities in southern Israel even after the Israeli military took back control, according to Israel Defense Forces spokesman Maj. Doron Spielman.

"We are in control of the communities, but we actually assume that there are Hamas terrorists that are still hiding in these areas, including in the road where we are now," Spielman told ABC News during an interview Monday in Sderot, Israel. "In all these communities, we've seen terrorist come out of hiding. Just yesterday, they took over an ambulance."

"We're still being very, very careful," he added. "This is a war zone with active terrorists that are operating here."

Sderot is a southwestern Israeli city located near the county's border with the Hamas-ruled Gaza Strip. A police station there was stormed by Hamas fighters on Saturday as part of the militant group's wider incursion, leaving at least six Israeli police officers dead. The IDF then bombed the police station with the Hamas fighters inside, demolishing it.

Hamas fighters and other Palestinian militants are "striking strategic locations" along the border fence, allowing them to drive through in pickup trucks, Spielman said. Civilians in some of the local communities have been ordered to evacuate, while others have left voluntarily, according to Spielman.

"We do have a lot of ground troops in this area. We have a lot of tanks. We have, in addition, artillery. And we're prepared forever for anything," he said. "And if it happens, the next stage, it's going to happen here because this is the area that was the flashpoint and this is the area we're going to be presenting ourselves and finishing this battle. We, of course, have no choice but to finish."

When asked about the mounting casualties of Palestinian civilians in Gaza as a result of the IDF's retaliatory airstrikes, Spielman said: "We always try to avoid civilian casualties. However, I would say that this is war and our first priority here is to destroy Hamas."

-ABC News' Angus Hines and Ian Pannell