Middle East markets have fallen after the lifting of Iranian sanctions and the country's promise to resume crude oil exports.
It stokes worries of the market's over supply which has already sent oil prices below $30.
The Saudi Tadawul All Share Index fell 5.4 per cent to its lowest since March 2011. The Qatar Exchange, the second largest in the Gulf after Saudi Arabia, dropped more than seven per cent. Markets in Dubai, Abu Dhabi, Kuwait, Egypt and Oman also closed lower on Sunday, the first day of the week for trading in the Middle East.
Iran plans to increase production by as much as half a million barrels a day according to a local news agency.
The lifting of sanctions after a landmark deal involving the end of its nuclear programme will reopen the Iranian economy to the rest of the world.
President Rouhani today called the milestone "a new chapter".