Israeli tanks and aircraft struck militant positions in the Gaza Strip on Thursday soon after Palestinian militants fired mortar shells at an Israeli military post close to the territory, the Israeli army said.
The mortar fire sent off several Code Red sirens in areas of southern Israel near the border with Gaza, though the Israeli military first said the sirens were a false alarm.
No Israelis were injured in the attack.
The army confirmed shortly thereafter that they had targeted "two additional military posts belonging to terror organizations in the Gaza Strip".
Problems in implementing the October accord have included how to resolve the issue of two separate civil adminstrations as well as security control of the Gaza Strip, with Hamas refusing to disarm. Service resumed about two hours later.
No injuries were reported on either side of the fence dividing the Gaza Strip from Israel. But the tunnel incident also has increased friction between Israel and Islamic Jihad, the second-largest militant group in the strip, which had threatened revenge for the deaths of its fighters.
Rival Palestinian factions Fatah and Hamas agreed on Wednesday to delay the final transfer of power over the Gaza Strip from Hamas to the Western-backed Palestinian Authority government by 10 days to December 10 to allow time to "complete arrangements", officials said.
"The Palestinian resistance has the full right to defend and respond to this unsafe escalation".
Israeli forces have maintained regular incursions into the Gaza Strip along both the land and seaside borders. A total of 67 Israeli soldiers and six Israeli civilians were killed in the conflict, while 2,251 Palestinians died, according to the United Nations.