JERUSALEM, Feb. 3 (Xinhua) -- Israeli fighter jets struck two targets at a Hamas military complex in the southern Gaza Strip early Saturday, in response to the projectile fired at southern Israel Friday evening from the Gaza Strip, said the Israeli Defense Forces (IDF) Saturday.

The IDF reiterated in the statement that the army "holds Hamas accountable for all violence emanating from the Gaza Strip."

The IDF's airstrikes came hours after a rocket was fired from the strip, setting off warning sirens in the southern Israel. No one was hurt and no damage was caused by the rocket fire.

Early Friday morning, an Israeli aircraft targeted a Hamas observation post in the northern Gaza Strip in retaliation for earlier rocket fired by Hamas from the Gaza Strip at southern Israel, according to the statement made by the Israeli Defense Forces (IDF).

This round of Hamas rocket fire and the IDF airstrike happened after nearly one month of relative calm. The last attack from the Gaza Strip took place at the beginning of January when three mortars were fired from Gaza at southern Israel, causing no injuries or damage.