Israeli forces fired on two positions used by UN peacekeepers in Lebanon on Thursday and at a third one on Wednesday, the UN force said, as Israel warned Lebanese civilians not to return to homes in the south and pressed on with its assault on Hezbollah, Reuters reports.

The United Nations Interim Force in Lebanon (UNIFIL) said two of its peacekeepers were injured in one of the incidents, when an Israeli tank fired at a watchtower at the force's main headquarters in Naqoura, hitting the tower and causing them to fall. There were no casualties in the other two incidents, a UN source said.

"Any deliberate attack on peacekeepers is a grave violation of international humanitarian law," UNIFIL said in a statement, adding that it was following up with the Israeli military.

UNIFIL said Israeli soldiers had also fired at a UN position in Ras Naqoura "hitting the entrance to the bunker where peacekeepers were sheltering, and damaging vehicles and a communications system."

"An IDF [(Israel Defense Forces)] drone was observed flying inside the UN position up to the bunker entrance," UNIFIL said. The previous day, Israeli forces had "fired at and disabled the position’s perimeter-monitoring cameras," it added. They also deliberately fired at and damaged another position, it said.

The Lebanese health ministry said an Israeli strike overnight hit a civil defense center in the village of Derdghaiya, some 10 km (6 miles) from the border, killing five paramedics and rescue workers.

The UNIFIL peacekeeping force was established in 1978 and expanded following a 2006 war between Israel and Hezbollah. Its major contributing nations include France, Italy, Indonesia, Malaysia, and Ghana.