Tensions between Iran and Saudi Arabia rose on Wednesday as Iran's Supreme Leader Ayatollah Ali Khamenei threatened a "tough and harsh" response over Saudi Arabia's failure to quickly repatriate the bodies of hajj stampede victims.

"Saudi Arabia failed to fulfill its duties concerning the desperate wounded [pilgrims]," Khamenei said at a military academy Wednesday, according to Iran's official PressTV. "Should we decide to show any reaction, our reaction will be tough and harsh."

At least 239 Iranians were killed in last Thursday's hajj stampede near the Muslim holy city of Mecca, and another 241 are reportedly unaccounted for, according to AFP. In all, Saudi officials estimate that at least 769 people were killed and more than 900 injured, with many bodies still unidentified.

Iran has become increasingly frustrated at Saudi Arabia's refusal to allow a cargo plane into the country to bring the dead home, and for the fourth time in six days summoned the Saudi ambassador, demanding that the bodies be quickly identified and repatriated.

"Saudi authorities do not discharge their responsibilities and in some cases act contrarily [to their duties] and slyly," Khamenei added. "The Islamic Republic of Iran has so far showed self-restraint and abided by Islamic politeness and brotherhood."

Khamenei urged for the creation of a fact-finding committee of Muslim nations, including Iran, to investigate the tragedy, according to Iran's Ministry of Foreign Affairs.

He also criticized the Saudis for failing to ensure the safety of the hajj pilgrims, saying, "Our nation is grief-stricken; the Hajj should be a place of security; is it [called] security when the lives of people are jeopardized during the [Hajj] rituals?"

The two countries have already been at each other's throats over Iran's support of Shiite rebels in Yemen, which borders Saudi Arabia to the south. Saudi Arabia joined together with other Arab countries to form a coalition to fight them off.

Iranian President Hassan Rouhani blamed Saudi Arabia's "ineptitude" for the deaths on Sunday, suggesting that the kingdom had sent experienced military troops to intervene in Yemen and therefore didn't have enough security personnel to maintain order at the annual hajj event, as HNGN previously reported.