A senior Hamas official accused Israel of unilaterally overturning the ceasefire agreement.
The Israeli army did not provide more details about the strikes, but Prime Minister Benjamin Netanyahu's office released a statement saying the military had been instructed to "take strong action against the Hamas terrorist organisation".
"This follows Hamas's repeated refusal to release our hostages, as well as its rejection of all of the proposals it has received from US Presidential Envoy Steve Witkoff and from the mediators," the statement added.
"Israel will, from now on, act against Hamas with increasing military strength."
Three houses were hit in Deir Al-Balah in central Gaza, a building in Gaza City, and targets in Khan Younis and Rafah, according to medics and witnesses.
The Palestinian civil emergency service said there were at least 35 airstrikes on Gaza.
The escalating violence comes amid disagreement between Israel and Hamas on how to sustain the three-phase ceasefire that began in January.
Arab mediators, backed by the United States, haven't been able to hammer out differences between the two warring parties in talks held over the past two weeks.Â
A senior Hamas official told Reuters on Tuesday that Israel is unilaterally ending the Gazaceasefire agreement.
The administration of President Donald Trump was consulted by Israel on its strikes on Gaza on Monday, a White House spokesperson told Fox News.
