Iran blamed Israel and the US on Wednesday for twin bomb blasts that killed at least 95 people in the country's south, ripping through a crowd commemorating Revolutionary Guards general Qasem Soleimani four years after his death in a US strike. 

The two explosions — labeled a "terrorist attack" by state media and regional authorities — came amid high Middle East tensions over the Israel-Hamas war in Gaza and the killing of a Hamas senior leader in Lebanon on Tuesday. 

The unclaimed attacks, which sparked fears of a widening conflict in the region, rattled global markets where oil prices jumped more than three percent and sparked global condemnation.

"Washington says USA and Israel had no role in terrorist attack in Kerman, Iran. Really? A fox smells its own lair first," the Iranian president's political deputy, Mohammad Jamshidi wrote on X, formerly Twitter.

"Make no mistake. The responsibility for this crime lies with the US and Zionist regimes (Israel) and terrorism is just a tool," he added. 

The United States had earlier rejected any suggestions that it or ally Israel were involved while Israel declined to comment.

"The United States was not involved in any way… We have no reason to believe that Israel was involved in this explosion," State Department spokesman Matthew Miller said.

Asked about the blasts, Israeli army spokesman Daniel Hagari said: "We are focused on the combats with Hamas."

Iran's supreme leader Ayatollah Ali Khamenei blamed "evil and criminal enemies" of the country for the attack and vowed a "harsh response". 

President Ebrahim Raisi, who scrapped a visit to Turkey on Thursday, condemned the "heinous" crime as the Islamic Republic of Iran declared Thursday a national day of mourning.

The blasts, about 15 minutes apart, struck near the Martyrs Cemetery at the Saheb al-Zaman Mosque in Kerman, Soleimani's southern hometown, as supporters gathered to mark his killing in a 2020 US drone strike in Baghdad.