Clashes between rival movements Hamas and Fatah have brought about renewed violence in the Gaza Strip, resulting in at least 41 deaths in six days.

The two groups attempted to ally with one another in March to end major clashes—but violence and crime remains widespread in the region.

Also, Palestinian militants fired at least 28 rockets into southern Israel, killing one and wounding more than 20 others. The attack was an apparent attempt to stop the renewed factional fighting and unite Hamas and Fatah against Israel, which both want to see destroyed.

The Israeli military reacted swiftly to the rocket fire, sending rocket-armed fighter jets to a Hamas military base in southern Gaza. The attack reportedly killed at least five militants.

As the rival factions continue to fight one another, Israel warned it would continue to retaliate in a “measured fashion” to protect its citizens.

The Israeli defense minister said the country “does not want to get involved in inter-Palestinian hostilities, but will react severely.”