The skies over Gaza and central Israel were filled with smoke this week and sirens blared in dozens of Israeli towns and cities as Operation Protective Edge continued to pound Hamas targets in what is being described as an all-out attack against the terrorist organization.

By July 9, the second day of the operation, the Israeli air force had expanded its offensive, hitting some 440 targets in Gaza, according to Israel Defense Forces estimates.

Hundreds of rockets have been launched from Gaza into Israel, including long-range weapons aimed toward Tel Aviv, Jerusalem, Hadera and as far north as the Hof HaCarmel Regional Council, near Haifa, where Home Front Command ordered public shelters to be opened.

Code red sirens have sounded throughout Israel’s southern and central regions, including in Rishon LeTzion, Modi’in and Ra’anana. One rocket shot the evening of July 8 landed in Hadera, two were intercepted over Tel Aviv and at least one rocket struck Jerusalem.

As of midweek, the IDF reportedly was considering a ground offensive into Gaza. More than 40,000 reservists were called up on July 8.

“The army is ready for all possibilities,” Prime Minister Benjamin Netanyahu said after a July 9 meeting with his Security Cabinet.

“Hamas will pay a heavy price for firing toward Israeli citizens. The security of Israel’s citizens comes first. The operation will expand and continue until the fire toward our towns stops and quiet returns.”

In the first two days of Operation Protective Edge, Israel struck more Hamas targets than it had in all of Operation Pillar of Defense, Israel’s eight-day offensive on Gaza in 2012, a top air force commander told the daily Haaretz. Military aircrafts dropped more than 400 tons of explosives in that period, after a heavy rocket barrage was fired at Israel.

“We think Hamas was surprised by Israel’s actions over these two days. We are systematically hitting their infrastructure, where Hamas commanders operate,” the officer added.

The Iron Dome missile-defense system intercepted nearly 90 percent of the rockets that appeared to target population areas, and 27 percent of the total number of rockets launched overall through July 9, according to Haaretz.

At least two rockets were aimed at Ben Gurion Airport and intercepted during morning rush hour, according to Palestinian sources cited by Israeli media. Heavy traffic was stopped on freeways into Tel Aviv as warning sirens were heard throughout the city.

Defense Minister Moshe Ya’alon said on July 9 that the operation was set to expand, and similar comments were made by the IDF spokesperson, indicating Israel was still mulling a ground operation in Gaza.

“We’ll continue with strikes that will exact a very heavy price from Hamas. We are destroying arms, terror infrastructures, command systems, Hamas institutions, regime buildings, terrorists’ houses and killing terrorists of various ranks of command,” the defense minister told Army Radio.

“We will continue to hit Hamas and other terror groups in Gaza Strip from the air, sea and ground to ensure the safety of Israel’s citizens,” he added.

On July 8, the military struck about 160 of what it called terror sites in the Gaza Strip, according to an IDF statement. Among the sites hit were 118 concealed rocket launching sites, weapon storage facilities, 10 tunnels, six Hamas facilities and 10 terror command positions.

Israel launched Operation Protective Edge in the very early hours of July 8 to stop the firing of rockets on Israel — what Netanyahu called a “significant expansion” of the military’s operation against Hamas and other terrorist organizations in Gaza. He joined Ya’alon in urging Israelis to be patient, saying the operation could “take some time.”

“Israel will not tolerate the firing of rockets on our cities and towns,” Netanyahu said in a statement. “No other country lives under such a threat, and no country would accept such a threat.”

The White House has slammed the rocket attacks against Israel.

“We strongly condemn the continuing rocket fire inside of Israel and the deliberate targeting of civilians by terrorist organizations in Gaza,” White House spokesman Josh Earnest told reporters July 8. “No country can accept rocket fire aimed at civilians, and we support Israel’s right to defend itself against these vicious attacks.”

At least four Palestinians were reported killed in Israeli airstrikes early on July 9, including an 80-year-old woman. As many as 53 Palestinians were killed in Israeli airstrikes in the first two days of the operation, according to the Palestinian Ma’an news agency.

Israel has been calling the homes of Palestinian civilians in Gaza to warn them to evacuate before launching airstrikes in their neighborhoods, the New York Times reported.

Deputy Defense Minister Danny Danon, meanwhile, demanded that the Security Cabinet cut off Gaza’s gas and electricity.

“Supplying electricity and fuel to Gaza Strip must be halted,” Danon said. “It’s inconceivable that while we are fight Hamas we supply them electricity and fuel used for firing rockets at us.”

Tel Aviv Mayor Ron Huldai urged the city’s residents to remain calm, saying the city will continue “business as usual.”

The U.S. Embassy in Tel Aviv has closed until further notice, a statement posted to its Facebook page read. The embassy has advised all U.S. citizens to stay updated via official U.S. travel websites, and to follow instructions from Israel’s Home Front Command. Embassy families are being advised to remain at home.