The air strikes were part of a broad Israeli offensive launched by Prime Minister Ariel Sharon against Islamic Jihad fighters who claimed responsibility for a bombing that killed five Israelis in an open-air market on Wednesday.
In most of Israel's dozen raids, warplanes targeted rocket launch sites in open areas of northern Gaza, from where militants have fired rockets, mortars and anti-tank rockets at Israel since Friday.
But several bombs dropped by Israeli jets struck near homes and police stations, made deep holes in roads and damaged a generator, cutting electricity to thousands of homes, Palestinian witnesses and security sources said.
Israeli warplanes also staged a series of mock raids, creating deafening sonic booms throughout the coastal strip.
Israel's bombings persisted despite international calls on both sides to show restraint and what appeared to be a respite in rocket launchings on Saturday.
In a statement on Saturday, Palestinian Interior Minister Nasser Youssef urged "immediate international intervention" to stop the raids.
Between the raids, the Israeli army dropped leaflets in Gaza threatening more strikes until there was "a total cessation of terror attacks". They also warned civilians to keep a distance from rocket launch sites and urged them to turn in fighters.
Youssef called for immediate
Nine Palestinians died in Israeli air strikes in Gaza on Thursday and Friday.
According to the Palestinian Centre for Human Rights, seven of the dead were two members of Islamic Jihad and five civilian bystanders, including three children.
In his statement, Youssef urged fighters to adhere to an eight-month truce with Israel and vowed to crack down further on those carrying illegal arms.
"We will deal firmly and seriously with any foundry or workshop that manufactures weapons or explosives and also any place used as storage for arms," Youssef said.
"We will not enter Palestinian houses to search for arms, but we will not spare any effort to confiscate every weapon we find in the streets," he added.
A spokesman for the Palestinian Authority, Nabil Abu Rdainah, said in a statement: "We urge the United States to work with the Israeli side for a ceasefire and to halt Israeli air strikes immediately in order to maintain the calm."
Israel's Deputy Premier Shimon Peres criticised his country's failure to hold talks with Palestinian leaders despite the offensive.
Peres criticised Israel's failure to
hold talks with the Palestinians
Sharon also said he would meet with Palestinian President Mahmoud Abbas only after Abbas took "serious action" against armed groups.
Abbas has sought to persuade fighters to stick to a truce he called with Sharon in February rather than disarm them by force, which he fears can cause a civil war.
Peres told Israel Radio that the militants were a common enemy of Israel and the Palestinian leader.
"We must speak to Abu Mazen," Peres said, using a nickname for Abbas. Israel should "fight terror mercilessly and aggressively, and find ways to resume the peace process."