Israeli planes have bombed a smuggling tunnel into Gaza after Palestinian mortars fell near the main crossing from Gaza into Israel.
The Israeli military said two mortar shells landed a few hundred metres from Erez crossing as urgent Palestinian medical cases were being transferred.
It was the first such airstrike since mid-June, with Palestinian rocket attacks much reduced in recent months.
No casualties were reported in any of the incidents.
The Israeli military said the air strike early on Monday morning was in response to "continued" rocket and mortar fire.
In addition to the mortar attack on Sunday afternoon, a rocket was fired into Israel on Sunday morning, the military said.
The Israeli military has often targeted the tunnels through which are goods are smuggled from Egypt into Gaza, bypassing Israel's crippling economic blockade of the territory.
Israel says weapons are also transferred through the tunnels.
Attacks by Gaza-based Palestinian militants have dropped in recent months, with two rockets and a mortar falling in Israel in July, and two rockets in June.
The Israeli military says about 700 rockets and mortars have been fired into Israel since the start of the year - which includes most of Israel's 22-day military offensive in December and January.
Israel says the operation and the blockade are aimed at ending rocket fire and weakening the Hamas movement which controls Gaza.
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