Iran's Rouhani calls for investigation of Saudi Arabia by the UN after Hajj stampede

The recent stampede at the annual Muslim pilgrimage to Mecca known as Hajj claimed the lives of 769 people and injuring 934, many of whom were from Iran. Saudi Arabia has been heavily criticized by Iran, with accusations of incompetence and negligence being directed at the Saudi government.

It can be argued that Iran has used this disaster to its advantage, Iran is Saudi Arabia's biggest rival in the region as competition for influence grows.  Iran took the opportunity to denounce the Saudis, other Islamic nations are also calling the Saudis competence regarding the organisation of the Hajj into question, causing tension among the Arab states. 

There is also a growing threat of Islamic State in Saudi Arabia, who have recently bombed several Shia mosques, there are fears that supporters of Islamic State will use the recent stampede as ammunition against the Saudi regime, adding more instability to an already dangerous region. Saudi Arabia's  leadership of the Arab states has been put in the spotlight in recent years, with falling oil prices, the continuing conflict in Syria as well as the controversial expansion of Mecca and Medina, which has destroyed relics dating back to Mohammed's time. Saudi Arabia has also been criticized for cantering to rich pilgrims at the expense of poorer ones, this divide has been partially blamed for the stampede as people were denied safety in tents owned by richer pilgrims, which could have been used to save lives. This stampede has damaged relations between Saudi Arabia and the rest of the Muslim world, coupled with the dangerous situation with Islamic state, Syria and the Saudi regimes' building new expensive hotels and shops in order to create greater revenue from Hajj, has drawn criticism from many Muslim nations.
Iran has called for a UN investigation of Saudi Arabia

http://www.bbc.com/news/world-middle-east-34368387