There were no reported Israeli or Gaza fatalities from the rocket fire.
After calm had been restored on Saturday, the Islamic Jihad spokesperson said that an Egyptian-mediated truce had been reached.
But IDF spokesman Lt. Col. Jonathan Conricus said the militant group, which is funded by Iran, coordinated the attack with Iran's al-Quds Revolutionary Guard Corps, which has forces in Syria.
The army said on Twitter that 14 rockets had been fired from Gaza towards Israel since late Friday but eight were intercepted by its Iron Dome missile defence system.
Earlier Saturday, the Islamic Jihad terror group announced it had agreed to an Egyptian-brokered ceasefire to end an escalating exchange of fire with Israel, as Israeli jets struck sites in the Gaza Strip belonging to the Palestinian terror organization.
On Friday, six Palestinians died in renewed clashes on the Gaza-Israel border, while Hamas said Egypt was seeking to negotiate a return to calm.
After several hours without rocket alert sirens in Israel's border communities, the IDF said civilians living in the Gaza vicinity could return to routine on Saturday afternoon.
Israel and Hamas have fought three wars since 2008 and much of the global community considers the Islamist movement a terrorist organisation.
Earlier on Friday, thousands of Palestinians gathered at five locations along the border, burning tires and throwing rocks and firebombs at Israeli troops, who responded with tear gas and occasional live fire.
Egypt wants to restore calm in order to pursue the broader goal of Palestinian reconciliation between Hamas and the West Bank-based administration of President Mahmoud Abbas.
Gaza's Ministry of Health, meanwhile, said that air strikes had targeted the perimeter of the Indonesian Hospital in Beit Lahiya in the northern Gaza Strip, causing material damages to the building.
Three of the men were shot dead east of Khan Yunis in southern Gaza, while one was killed east of Jabalia in the north of the coastal territory, the health ministry said.
The announcement came after the PIJ took credit for launching over 30 rockets at Israel on Friday and Saturday, with Israel retaliating with a large-scale assault on 80 Hamas military targets in Gaza.
He added the group "will be committed to the deal as long as Israel is committed to".
Israel says it keeps a naval blockade and tight control of its land crossings with the enclave for security reasons.
Israel has struck Syria dozens of times in recent years, saying it is preventing Iran from supplying advanced weapons to enemies of the Jewish state.