Iran’s Supreme Leader Ayatollah Ali Khamenei delivered perhaps his harshest comments against regional rival Saudi Arabia ahead of the annual hajj pilgrimage.

During last year’s hajj pilgrimage, 472 Iranians were killed in a stampede in the city of Mina. More than 2,000 people were killed in the stampede, according to news agencies. Saudi authorities at the time denied the high death toll, claiming it was closer to 700 people. A number of prominent Iranian officials, including Iran’s former ambassador to Lebanon, were killed in the stampede.

In a statement addressed to all Muslims, Khamenei said that instead of apologizing for the stampede or allowing a Muslim international body to investigate what happened, Saudi authorities accused others of wrongdoing. In his response to the stampede, Khamenei accused Saudi officials of “murder,” saying that they left the injured with the dead rather than providing them with medical treatment.

The high death toll and accusations of mismanagement led to prolonged negotiations between the officials from each country over this year’s hajj. The two sides were ultimately unable to come to an agreement, and Iranian pilgrims were prevented from attending hajj this year. Saeed Ohadi, the head of Iran’s hajj and pilgrimage organization, accused Saudi Arabia of being “domineering” during those negotiations and creating obstacles. He said that Saudi Arabia dragged out talks over the issues of using Iranian planes, attendance of Iranian physicians and tracking devices for Iranian pilgrims. Saudi authorities accused Iran of wanting to hold protests during hajj.