JERUSALEM, June 13 (Xinhua) -- Israeli military said on Thursday that it had struck a Hamas tunnel in the Gaza Strip after a rocket was launched toward southern Israel overnight.

Israeli fighter jets targeted "a terror underground infrastructure" in the southern Gaza Strip, a military spokesperson said in a statement.

The tunnel was located in a military compound belonging to Hamas, an Islamist Palestinian group that runs the besieged coastal enclave.

According to the military, the airstrike came in retaliation for a rocket launched earlier from Gaza toward the Eshkol Regional Council in southern Israel.

Israel's Iron Dome air defense system intercepted the rocket and no damage or injuries were reported, it said.

No group immediately assumed responsibility for the rocket attack but the military said it holds Hamas "accountable for all events transpiring in the Gaza Strip and emanating from it."

"The IDF (Israel Defense Forces) will continue operating against any attempt to harm Israeli civilians," the military warned.

Meanwhile, Islamic Jihad Spokesman Daoud Shihab said the Palestinians are determined to continue with the implementation of the cease-fire understandings despite "Israel's attempts to sabotage it," according to a report on Israel's Ynet news site.

The rocket fire came hours after Israel announced it was imposing a naval blockade on Gaza "until further notice," citing helium-filled incendiary balloons that were launched into Israel's southern farmland.

The escalation was the first flare-up between Israel and Gaza since a cease-fire was announced in May after the worst violence between Israel and Hamas since the last full-fledged war in Gaza in 2014.

The Gaza Strip, home to about 2 million people, has been under an Israeli blockade since 2007. Under the blockade, Israel strictly limits exit and entrance of people and goods, inflicting a humanitarian crisis on the territory.