The strikes began late on Friday and continued into Saturday morning, among others killing 12 people at the Palestine Stadium in Gaza City, which was sheltering displaced people, and eight more living in apartments, according to staff at Shifa hospital where the bodies were brought.
Six others were killed in southern Gaza when a strike hit their tent in Muwasi, according to the hospital.
The strikes come as US President Donald Trump says there could be a ceasefire agreement within the next week.
Taking questions from reporters in the Oval Office Friday, the president said, "We're working on Gaza and trying to get it taken care of."
An official with knowledge of the situation told The Associated Press that Israel's Minister for Strategic Affairs, Ron Dermer, would arrive in Washington next week for talks on Gaza's ceasefire, Iran and other subjects.
Talks have been on again, off again since Israel broke the latest ceasefire in March, continuing its military campaign in Gaza and furthering the Strip's dire humanitarian crisis.
Some 50 hostages remain in Gaza, fewer than half of them believed to still be alive.
They were part of some 250 hostages taken when Hamas attacked Israel on October 7, 2023, sparking the 21-month-long war.
The war has killed more than 56,000 Palestinians, according to Gaza's health ministry, which does not distinguish between civilians and combatants.
It says more than half of the dead were women and children.
There is hope among hostage families that Trump's involvement in securing the recent ceasefire between Israel and Iran might exert more pressure for a deal in Gaza.
Israeli Prime Minister Benjamin Netanyahu is riding a wave of public support for the Iran war and its achievements, and he could feel he has more space to move towards ending the war in Gaza, something his far-right governing partners oppose.
Hamas has repeatedly said it is prepared to free all hostages in exchange for an end to the war, while Netanyahu says he will end the war only when Hamas is disarmed and exiled, something the group has rejected.
Hungry Palestinians are enduring a catastrophic situation in Gaza.
After blocking all food for two-and-a-half months, Israel has allowed only a trickle of supplies into the territory since mid-May.
Palestinians have been shot and wounded while on their way to get food at newly formed aid sites, run by the American and Israeli backed Gaza Humanitarian Foundation, according to Gaza's health officials and witnesses.
Palestinian witnesses say Israeli troops have opened fire at crowds heading towards the sites.
Israel's military said it was investigating incidents in which civilians had been harmed while approaching the sites.