TEHRAN - South Africa has strongly condemned Israel's assassination of Ismail Haniyeh, head of the political bureau of the Palestinian resistance movement Hamas, in Tehran.

In a statement released on Thursday, the South African Foreign Ministry said it is concerned that the assassination of Haniyeh and the continuous targeting of civilians in Gaza will further spiral the already tense situation in the entire region.

"South Africa urges that a thorough investigation be conducted and calls on all parties to exercise the utmost restraint to avoid any acts that would escalate tensions in the particularly fragile region," the statement read, Press TV reported. 

South African Foreign Minister Ronald Lamola also said Haniyeh’s assassination was extrajudicial killing and violated international law. 

“Such acts of extrajudicial killings violate international law and the principles of human rights, undermining global efforts to promote peace and stability in the Middle East,” the top diplomat said. 

"Any form of extrajudicial killing is a blatant violation of these principles and extra judicial killings of this nature have a destabilizing effect. It is crucial that the perpetrators of such actions must be brought to justice."

Lamola said Haniyeh’s assassination occurred in the context of the months-long slack in Gaza, where the ongoing Israeli onslaught has killed more than 39,000 Palestinians, most of them women and children.

He said Haniyeh was an integral member of the negotiating team, working with mediators to secure a permanent ceasefire and bring the war in Gaza to an end.

Elsewhere in his remarks, Lamola said Israeli’s continued occupation, destruction of infrastructure, collective punishment and extrajudicial assassinations would make the realization of a peaceful solution in West Asia much more difficult to achieve.