The UN’s special coordinator for the Middle East peace process said on Wednesday that ongoing escalations undermined efforts to improve socio-economic conditions in Gaza.

“I am very concerned about the ongoing and serious escalation between Palestinian Islamic Jihad and Israel, following the targeted killing of one of the group’s leaders inside Gaza yesterday,” Nickolay Mladenov said in a statement.

Mladenov stressed that there could be no justification for any attacks against civilians.

“The indiscriminate launching of rockets and mortars against population centers is absolutely unacceptable and must stop immediately.

Read more: Continuing escalation very dangerous in Gaza: UN envoy