The Israel Defense Forces (IDF) announced Tuesday the deployment of a tactical radar system in southern Israel, designed to warn residents of incoming mortar attacks from the Gaza Strip.

The move came amid rocket fire Tuesday night, shortly after 21:00, when alarms sounded in southern Israel. Five rocket launches were detected as being fired from the Gaza strip, after a month of quiet.

According to an IDF Spokesperson, four launches were declared erroneous. It is presumed the four rockets landed inside the Gaza strip. A fifth rocket hit Israeli territory at an undisclosed location near the city of Ashdod.

Israeli Air force jets were circling Gaza airspace, though the IDF said it will not retaliate with fire at this point.

A directive has been issued to reopen bomb shelters and protected areas in the relevant areas of Israel.

The new radar system has so far been installed in several communities along the Israel-Gaza border, and the IDF believes the installation will be completed by September. The decision to deploy the system followed IDF assessments suggesting the next conflict with Gaza-based terrorist groups will see them targeting border-adjacent communities with short-range projectiles.

The IDF believes the terrorist groups operating in Gaza understand that while the Iron Dome missile defense system can intercept 90 percent of the projectiles fired at populated areas in Israel, it has struggled to neutralize mortar shells, which have a range of up to 1 kilometer (six-tenths of a mile).

The military’s assessments are based, among other things, on the last days of Operation Protective Edge last summer, which saw incessant mortar fire at the border and nearby communities. Some 2,580 mortar shells were fired at the border-vicinity communities during the 50-day military campaign, five of which killed Israelis.