Israel launched retaliatory air strikes on the Gaza Strip Thursday hours after its top soldier warned troops to be prepared for possible "wider action" on the enclave's volatile border.

An Israeli military spokeswoman said the strikes were aimed at three separate targets, two of which Gaza militants confirmed were sites they used for training. No casualties were reported. The air strikes were launched overnight after a mortar fired by Gaza militants wounded an Israeli man at a farm.

"The situation on the Gaza Strip border is fragile these days," Israeli armed forces chief General Gaby Ashekenazi told troops based near the Gaza border, according to the Maariv daily. Ashekenazi cited a large number of explosive devices on the border and rising activity against Israel at the northern edge of Gaza, predicting more incidents.

"We may need to be prepared for wider action. The next round will be big and it needs to end in a way that leaves no doubt who won. We are significantly stronger than the other side," the commander said, according to Maariv. Militants in the enclave ruled by the Islamist Hamas faction have fired some 200 rockets and mortars at Israel this year, the Israeli army says.