JERUSALEM (Reuters) - An explosive device wounded four Israeli soldiers, two severely, near the border fence with the Gaza Strip on Saturday, spurring Israeli air strikes later in the day against Palestinian militant targets.

There was no immediate claim of responsibility for the explosion, which occurred along the southern frontier of the territory, controlled by the Islamist group Hamas.

“Today’s incident on the Gaza Strip border is severe. We will respond appropriately,” said Israeli Prime Minister Benjamin Netanyahu.

Israeli media said it was the highest number of Israelis wounded in a single incident since the 2014 Gaza war.

An Israeli army spokesman said the explosive device had been hidden near the fence a day earlier, attached to a flag, during a Palestinian protest along the border.

In response, he said, the military struck six targets in Gaza including a weapons manufacturing site and an underground tunnel for militants being built in the direction of Israel.

Palestinian officials said the Israeli attacks included air strikes against three Hamas training camps and a fourth belonging to a smaller militant group, causing no injuries.