No group immediately assumed responsibility for the rockets, but previous rockets have been launched by the Palestinian Islamic Jihad, in retaliation for the killing of one of its top commander in an Israeli strike on Tuesday.
After two days of violence - in which 34 Palestinians died and there were no Israeli fatalities - a ceasefire agreement was reached.
Deputy spokesman for UN Secretary-General Antonio Guterres, Farhan Haq, said that the UN chief demanded the Israeli entity to swiftly open an investigation into targeting a family of which eight members were killed in an Israeli missile strike on Gaza.
A military spokesperson told Efe news that this was the first time in the last few days that Israel had struck Hamas targets.
Hamas administers the Gaza Strip.
Israel blamed the commander, Baha Abu al-Ata, for most of the rocket attacks and other terrorist activity from Gaza in recent months.
No injuries were reported by Israeli army.
Breaking the truce that was agreed on earlier this week, Israel on Saturday confirmed that it had targeted several Hamas sites during predawn airstrikes in the Gaza Strip.
"Every child in Gaza knows that senior activists live in different conditions, they have houses, and even when they go underground their children and families don't live in such squalor", he said. The Israeli military said the Iron Dome missile defense system intercepted 90 percent of rockets headed toward residential areas and 60 percent landed in open fields. "The subject of his identity, as well as the harm caused to civilians by the strike, is being further reviewed".
A shaky ceasefire in and around Gaza has been tested after two rockets were fired towards a town in Israel.