Israel says it launched the offensive on Tuesday in response to weeks of heavy rocket fire out of Gaza. The Israeli military says it has hit more than 1,100 targets, mostly what it identified as rocket-launching sites, bombarding the territory on average every five minutes.
At least 21 Palestinians were killed Friday, pushing the overall death toll to 106, including dozens of civilians, according to the Health Ministry in Gaza.
Palestinian militants have fired more than 600 rockets at Israel, including one that struck a gas station and set it ablaze earlier Friday in the southern city of Ashdod. Israeli health officials said the blast wounded three people, including one in serious condition.
The army also said the condition of a soldier wounded by rocket shrapnel on Thursday had worsened. But there have been no deaths on the Israeli side, in large part because of a new rocket-defense system that has intercepted at least 128 incoming projectiles.
Netanyahu said he has been in touch with numerous world leaders, including President Barack Obama and the leaders of Britain, France, Germany and Canada.
He said he had "good discussions" with his counterparts, telling them that no other country would tolerate repeated fire on its citizens.
"No international pressure will prevent us from acting with all power," he said.
Israel's allies have backed the country's right to self-defense, but they have called for restraint. U.N. Secretary-General Ban Ki-moon has expressed concern about the heavy civilian casualties in Gaza, and on Friday, the U.N.'s top human rights official said the air campaign may violate international laws prohibiting the targeting of civilians.
"We have received deeply disturbing reports that many of the civilian casualties, including of children, occurred as a result of strikes on homes," said Navi Pillay, the U.N. high commissioner for human rights.
"Such reports raise serious doubt about whether the Israeli strikes have been in accordance with international humanitarian law and international human rights law," she said.
Netanyahu brushed aside such criticism, saying Israel's aerial campaign is aimed at military targets.
He blamed Hamas for causing civilian casualties by hiding in residential areas and criticized the group for targeting Israeli population centers.
Israel has massed thousands of troops along the border in preparation for a possible ground invasion. Netanyahu was evasive when asked about the odds of a ground operation, saying only: "We are weighing every possibility."
Rocket fire continued in earnest from Gaza toward various locations in southern and central Israel. The commercial center of Tel Aviv and Ben-Gurion airport, Israel's main international gateway, also heard warning sirens Friday but these rockets were intercepted and there was no disturbance to Israel's air traffic. Hamas says it intends to fire rockets at the airport and warned foreign airlines to stop flying to Israel.
Militants in Lebanon also took aim at northern Israel with rockets for the first time in the conflict. Rocket fire struck near the border between the two countries and the military responded with artillery fire toward the source in southern Lebanon, military spokesman Lt. Col. Peter Lerner said.
The Lebanese military said militants there fired three rockets toward Israel and the Israelis retaliated by firing about 25 artillery shells on the area.
Lebanon's state-run National News Agency said that one of the militants firing the rockets was wounded and rushed to a hospital. The Lebanese military said troops found two rocket launchers and dismantled them.
Southern Lebanon is a stronghold of the Shiite militant group Hezbollah, which has battled Israel numerous times. However, recent fire from Lebanon has been blamed on radical Palestinian factions in the area and Hezbollah has not been involved in the ongoing offensive.
A pair of Lebanon-based al-Qaida-linked groups, the Battalions of Ziad Jarrah and the Abdullah Azzam Brigades, has claimed responsibility in the past for similar rocket attacks on Israel.