Israeli navy commandos have stormed a militant facility in the Gaza Strip sparking a brief gun-battle with the Hamas fighters.
The facility was being used as a rocket-launching site, said the Israeli Defence Forces (IDF).
This is the first such gunfight confrontation between the two sides since the rivals began firing off rockets in an aerial offensive that began six days ago.
The IDF said in a statement: "IDF forces raided a launching site used to fire long-range rockets at Israel. During the mission, there was an exchange of fire initiated by terrorists on site. Four soldiers were lightly injured and all returned home safely. The mission was accomplished."
The Hamas said they retaliated against Israeli forces in order to prevent them from advancing.
"Israeli has replied to the United Nations statement by killing 15 Palestinians. So Israel, by doing that, they have rejected the statement and we during this massacre confirmed that we will protect out Palestinian people and we will face the Israeli offensive. Fifteen martyrs killed in one moment," said Hamas.
The Israeli raid has come amid simmering fears that troops are gearing up for a ground invasion, with more than 20,000 reservists having been called up.
International communities including the UN have been imploring both sides to back down as civilian casualties continue to mount. The 15-member UN Security Council unanimously urged both sides to restrain from violence.
Saturday (12 July) was the bloodiest day since the six-day conflict began claiming the lives of at least 52 Palestinians.
So far, no less than 154 people in the Gaza Strip have been killed and the Palestinians say most of them are civilians.