Israel has again closed a major border crossing into Gaza after Palestinian militants fired a barrage of mortars and rockets into southern Israel.
Two people – believed to be Thai agricultural workers – were killed and 10 were injured on the Israeli side.
The crossing had been opened to allow entry to aid lorries from Jordan into Gaza. A separate convoy entered from Egypt.
A UN spokesperson said the Kerem Shalom crossing with Israel was a crucial link to get help to those in need.
At least 212 people, including almost 100 women and children, have been killed in Gaza, according to its health ministry. In Israel 12 people, including two children, have been killed, its medical service says.
On Tuesday Israel said at least 150 militants were among those killed in Gaza. Hamas, the Palestinian militant group that runs the territory, does not give casualty figures for fighters.
Israeli forces again shelled Gaza on Tuesday, the ninth day since the current violence began, while Palestinian militants fired a barrage of mortar shells into Israel.
The UN humanitarian agency Ocha said 52,000 people in Gaza had been displaced, of whom 47,000 had fled to UN schools.
What happened at the border crossing?
Earlier on Tuesday, Israel opened the Kerem Shalom crossing to allow aid into Gaza. The UN welcomed the decision, but also urged Israel to open the main Erez crossing, so that humanitarian workers, as well as supplies, could get in.
However, as the convoy of aid lorries entered Gaza, Palestinian militants fired mortars at the area. Two Thai nationals working on a farm 14km (nine miles) from the border were killed.
As a result, Israel closed the crossing again.
An Israeli soldier near Erez was slightly injured, the Israeli military said.
Meanwhile at the Rafah crossing with Egypt, the only entry point to Gaza not controlled by Israel, a separate convoy of 15 lorries carrying fuel and 18 loaded with food and medicine entered the territory.