Israel on Sunday reopened its crossings with the blockaded Gaza Strip after closing them during a deadly escalation earlier this month, an official said, as a fragile truce held.

Both the Erez crossing for people and Kerem Shalom crossing for goods were open and operating, a spokeswoman for COGAT, the defence ministry unit that oversees the crossings, said in a statement.

Both had been closed on May 4, when Gaza rulers Hamas and its ally Islamic Jihad fired hundreds of rockets at Israel, with the army striking dozens of targets in Gaza in response.

Four Israeli civilians and 25 Palestinians, including at least nine militants, were killed in the two-day flare-up, which ended on Monday in a tentative truce.

Palestinian officials said Israel had agreed to ease its crippling decade-long blockade of the impoverished enclave in exchange for calm.

Israel did not publicly confirm the deal, but on Friday lifted the ban it had imposed on Palestinian fishing boats operating off Gaza.

Israel says its blockade is necessary to isolate Gaza's rulers Hamas, with whom it has fought three wars since 2008.

But critics say it amounts to collective punishment of Gaza's two million residents.