Islamic Jihad fired a further volley of rockets and mortars from Gaza towards Israel Monday, following a flare-up between the group and the Jewish state that triggered school, road and train closures in southern Israel. 

Israel's army said in a statement that 20 "projectiles" had been fired from the Palestinian enclave on Monday, 18 of them intercepted by its air defence systems. Israeli police images showed that at least one of the projectiles landed in an empty children's playground.

On Sunday, in response to Israel's killing of a militant along the border, Islamic Jihad launched more than 20 rockets from Gaza into Israel. Israel's military said it responded to the rockets with airstrikes targeting "terror sites" throughout Gaza as well as near the Syrian capital.

The Damascus strike killed two Islamic Jihad fighters and four other Iran-backed militants allied to Syrian President Bashar al-Assad, according to the Syrian Observatory for Human Rights, a war monitor. Since the start of the Syrian conflict in 2011, Israel has carried out hundreds of strikes in Syria, mainly targeting government troops as well as allied Iranian forces and the Tehran-backed Lebanese group Hezbollah.

Israel rarely confirms responsibility for such strikes, but did so on Sunday, describing the target as a base "used as a hub" for Islamic Jihad activities in Syria.

Schools, roads closed

Israel took a series of precautions amid the rocket fire from Gaza. The education ministry ordered 65,000 students in towns near Gaza to stay home, postponing exams at universities in Ashkelon, Sderot and Netivot.

The transport ministry cancelled trains between Ashkelon and Beersheba, a major southern city roughly 50 kilometres (30 miles) from Gaza. The military said Zikim Beach on the Mediterranean Sea just north of Gaza had been closed to visitors.

Sunday's fighting was the most intense between Israel and Islamic Jihad since November, when an Israeli airstrike killed Rasmi Abu Malhous, described as a senior group commander. That strike also killed nine members of a Palestinian family unrelated to the armed group, and was followed by a three-day conflict that left 35 Palestinians dead and more than 100 wounded, according to official figures.

There were no Israeli fatalities. Islamic Jihad is allied with Hamas, the Islamist group that has controlled Gaza since 2007. But it has not accepted the informal truce Hamas has agreed with Israel in exchange for an easing of the crippling blockade on Gaza. Hamas and Israel last fought a full-scale war in 2014, but smaller flare-ups are relatively common.

Bulldozed

The latest escalation with Islamic Jihad came after Israel's military said Sunday it had killed a militant in Gaza who had tried to plant an explosive device near the border fence.

Israel later confirmed that it extracted the militant's body with a bulldozer. A video emerged later on social media, which was authenticated by AFP, showing a bulldozer approaching a body while a group of young, apparently unarmed men, were trying to retrieve it.

The sound of gunfire is heard and the men ultimately run away as the bulldozer scoops up the body. Israel's hawkish Defence Minister Naftali Bennett has pursued a policy of retaining the bodies of militants from Gaza as bargaining chips to pressure Hamas, which has held those of two Israeli soldiers since 2014.

Palestinian prime minister Mohammed Shtayyeh, speaking before a weekly cabinet meeting, called the bulldozer incident "a heinous crime." "(Israel's) occupation kills Palestinians in cold blood and with images that should shame humanity, and in violation of international law which Israel breaches day and night," he said.