Israeli Air Force jets on Monday afternoon bombed several targets in the Gaza Strip, after an early-morning rocket attack on Israel’s south.

“Three bombs were dropped by the air force on a Hamas military base east of Nusseirat refugee camp,” south of Gaza city, a Palestinian security source said.

The planes also made two raids against Hamas lookout posts along the border with Israel, east of Khan Yunis, and on a base of Islamic Jihad’s military wing in the north of the strip, the source said.

Israeli tanks along the border also fired at several targets, according to AFP.

Gaza’s health ministry said four Gazans were moderately injured by airstrikes east of Rafah, according to Palestinian reports.

“In response to a rocket fired from Gaza that hit Israeli territory last night, the IAF targeted 5 Hamas positions throughout the Gaza Strip,” the Israeli military said in a statement. “The IDF holds Hamas accountable for all attacks from the Gaza Strip that threaten Israel and her citizens.”

The rocket from Gaza, launched shortly before 4:15 a.m., hit the Sha’ar Hanegev region, northeast of the Gaza enclave, the military said. It struck an open field, causing neither damage nor injury.

In the two and a half years since Israel waged a war against Hamas in summer 2014, the number of rocket attacks against the Jewish state has dropped to historically low levels, approximately once or twice a month.

The nighttime attack was relatively uncommon, as rocket launches more frequently occur during the day, presumably to disrupt Israelis’ daily routines and to gain media attention.

These have been launched mostly by Sunni fundamentalist Salafist groups, not by Hamas. However, Israel holds Hamas, the Sunni terror group that has ruled the Strip for the past 10 years, as ultimately responsible for any rocket fire emanating from the Gaza Strip.

Monday morning’s rocket attack also comes two and a half weeks after a number of cross-border exchanges between Israel and terrorist groups inside the Gaza Strip, which raised concerns of potential renewed conflict between the IDF and Hamas.

On February 6, a rocket was launched at Israel’s southern Mediterranean coast, in the Hof Ashkelon region, striking an open field. Later in the day, an IDF patrol came under gunfire while on duty near the security fence.

The IDF responded to the two attacks with tank shellings and aerial strikes on a Hamas positions throughout the Gaza Strip.

Prime Minister Benjamin Netanyahu said at the time that Israel would not tolerate a “drizzle” of rocket attacks from the Gaza Strip “without a response,” as planes struck targets in the Strip.

“My policy is to respond strongly to any rocket fire,” Netanyahu said at the time. “We are firm in this response.”

In recent months, the IDF — under the direction of Defense Minister Avigdor Liberman — has adopted a harsher policy toward sporadic rocket fire.

The hawkish Liberman has promised that Israel will respond aggressively to rocket attacks, in order to force Hamas to rein in the more extreme groups in Gaza. On at least two occasions, the IDF carried out dozens of airstrikes on Hamas positions in response to rocket fire from Gaza.

Last week, the Islamic State in Sinai fired two missiles that struck an open field in Israel’s southern Eshkol region, on the border with Gaza and the Sinai Peninsula. And earlier this month, the terrorist group launched four Grad rockets at the southern city of Eilat. Three of them were intercepted by the Iron Dome missile defense system, while the fourth landed in an open field.

Dov Lieber and AFP contributed to this report.