Jerusalem, Ashkelon and Gaza CNN  — 

Tensions between Israelis and Palestinians have escalated further as Palestinian militants in Gaza fired hundreds of rockets into Israel, which responded with ramped up airstrikes on the coastal enclave, as unrest spread to cities and towns beyond Jerusalem.

As both sides traded airstrikes on Tuesday evening, Israeli Prime Minister Benjamin Netanyahu addressed the nation from Tel Aviv, saying, “We are in the midst of a significant operation.”

Israeli bombing raids across Gaza have killed at least 35 people, including 12 children, according to Palestinian health officials, who also said 220 people have been injured, as of Tuesday evening. The Israeli military said it had killed more than 15 militants.

Rockets were fired towards Tel Aviv in the early hours of Wednesday morning. Sirens could be heard warning of an impending attack around 3 a.m. local time. It was not immediately clear if there were any casualties.

Rockets are launched towards Israel from Rafah, in southern Gaza.

In the town of Ashkelon, two people were killed by rocket fire Tuesday, according to an Israeli military spokesman. A third person died in the town of Rishon Lezion, south of Tel Aviv on Tuesday evening after a rocket attack, Israeli media reported citing the ZAKA emergency service.

A CNN team heard at least 50 explosions in the coastal town near Gaza, and rocket fire was also reported in the city of Ashdod. At least 17 Israeli civilians have been treated for injuries from rocket attacks, the military said.

On Wednesday, Israel declared a state of emergency in the central city of Lod and dispatched border police battalions to the area for reinforcements, according to the Government Press Office. The mixed Jewish-Arab city has seen protests escalate into riots this week.

A CNN team driving through Lod early Wednesday saw roads strewn with rocks and burned out cars. Overnight, a rocket hit a house in Dahamesh, just outside the city, killing a 52-year-old man and his daughter, both Israeli-Arab citizens.

The Israeli military said in a morning briefing Wednesday that a total of five Israeli civilians have now been killed since the start of the violent exchange of rocket fire and airstrikes between Gaza and Israel earlier this week.

A 13-story building collapse

A 13-story tower block in Gaza city collapsed on Tuesday night after it was hit by an Israeli airstrike, drawing vows of retaliation from militants.

The Israel Defense Forces (IDF) said in a statement that the building contained offices used by Hamas across several floors, including intelligence offices of its military wing, and a research and development unit working on rockets.

The IDF also said it provided “advance warning to civilians in the building and provided sufficient time for them to evacuate the site.”

There are reports that one person on a nearby street was injured in the building’s collapse.

Separately, in the early hours of Wednesday, two separate buildings were hit, a three-floor residential building in which three people were killed, Gaza health officials said, and a 10-story building which suffered major damage but saw no fatalities. The larger building, known as the al-Jawahera building, houses media network companies and other offices.

Following the Israeli strike on the tower, a barrage of more than 200 rockets was then fired from Gaza into Israel.

Earlier Hamas had warned if residential tower buildings in Gaza were targeted, they would not sit idle and would respond with rocket fire.

The Izz ad-Din al-Qassam Brigades, the military wing of Hamas, says it responded with 210 rockets fired towards Beer Sheva and Tel Aviv.

Palestinian Ministry of Health spokesman in Gaza Ashraf, Al Qidra, said many Gaza residents are now in a state of panic due to the ongoing Israeli airstrikes.