Gaza's civil defence agency said 21 people were killed and dozens more wounded in multiple Israeli air strikes on Saturday, as Hamas and Israel again traded allegations of violating the fragile ceasefire.

Saturday was one of the deadliest days since the US-brokered truce between Israel and Hamas came into effect on October 10, after two years of war.

The Israeli military said an "armed terrorist" had crossed the so-called Yellow Line within the Gaza Strip, behind which Israeli forces have withdrawn, and fired at Israeli soldiers.

In response to the incident in southern Gaza, which it said was on a route used for humanitarian aid deliveries in the territory, the Israeli military said it "began striking terror targets in the Gaza Strip".

Mahmud Bassal, spokesman for the civil defence age

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