Israeli President Shimon Peres released a statement on Thursday expressing his condolences to the families of the victims of Wednesday’s terrorist attack on a bus carrying Israelis in Bulgaria. Peres blamed the attack on Iran, and hinted that Israel would retaliate.

“Yesterday we witnessed a terrorist attack unlike any other, perpetrated by Iran. We know that there were other attempts, and this time they succeeded. We will not forget, we will not ignore and we will not surrender. Israel will reach out and act regarding every terror nest around the world. It has the means to do so, and we are determined to act in this spirit.”

Iran has rejected charges that it was behind the attack.

On Thursday, Israel began airlifting some 34 wounded Israelis back to the country from Bulgaria, where an attack by a suicide bomber on Wednesday in the coastal resort town of Burgas killed 6 Israelis and a Bulgarian bus driver.

In the same statement, Peres related that Bulgarian President Rosen Plevneliev had called him Thursday morning to express his condolences to the victims of the attack.

Saying that the attack had “shocked all of Bulgaria,” Plevneliev said his country would do everything in its power to continue to aid the wounded Israelis.

“The Bulgarian nation feels a deep sense of closeness to the Israeli people,” he said, noting a history of friendly relations between the two nations and efforts by Bulgarians to save Jews during the Second World War.

The two leaders agreed that the proper response to the attack would be to strengthen strategic relations and security cooperation between the two countries.

In a statement released on Wednesday, French President Francois Hollande expressed “profound shock… disgust and condolences” over the attack, which he said was shared by all French people. “France will continue to remain vigilant and determined in the fight against terror, hate and intolerance.”

French Foreign Minister Laurent Fabius added that, “In these tragic circumstances, France expresses its complete identification with the Israeli authorities in their struggle against hate and terror.”