Air-raid sirens began to sound across southern Israel shortly after Israel conducted its air strikes, the Israel Defence Forces (IDF) said.
The rocket launch by militants in Gaza broke the lull which developed following a full-day of cross-border fighting between Israel and Hamas on Monday.
After darkness fell Monday night, a rocket launched from Gaza triggered sirens on the Israeli side of the border, the military said. It was unclear where that rocket landed.
There were no reports of casualties or damage.
A Palestinian official close to an umbrella group of Gaza armed factions said that the rocket firing was an “individual” act not sanctioned by them.
WATCH: Gaza residents sift through the ruins following Israeli airstrikes
Israel said one if its Monday air strikes destroyed the office of Ismail Haniyeh, chairman of the Hamas political bureau.
The country has said it reserves the right to strike again and has kept its troops and tanks massed at the Gaza frontier.
“If Hamas think that we’ll sit idly by as their rocket fire, explosives, and breaches of Israel’s border fence threaten the lives of Israeli civilians — they’re wrong,” the IDF said in a tweet.
— With files from Reuters