Oil prices sunk on Monday after a major meeting in Qatar designed to freeze output failed.

After months of hope for the outcome of the meeting, the disappointing failure will call OPEC’s credibility into question, as well as further flooding the market with unwanted oil. The meeting, which included most OPEC countries – with the exception of Iran – as well as some non-OPEC countries, fell to pieces after Saudi Arabia refused to sign a price freeze without the participation of rival Iran.

According to reports, Saudi Arabia said an oil freeze agreement must be signed by all 13 OPEC members – including Iran, who was never signed up to attend the meeting. The turnaround move by Saudi suggests that rivalry between the two countries in the Middle East appears to be more important to Riyadh than the freezing of oil output.

Iran have said that they will continue to increase output, following the lifting of sanctions against it:

“As we’re not going to sign anything, and as we’re not part of the decision to freeze output, we ultimately decided it was not necessary to send a representative,” the Iranian government said.

Qatari Energy Minister Mohammed Saleh al-Sada stated that consultation will continue between the countries until the June OPEC meeting:

“All participating countries will consult among themselves and with others,” he said.

Oil prices tanked on the news of the failure, with Brent Crude falling around 7 percent, before recovering to $41.23 a barrel. US Crude also saw a similar fall and recovery, now standing at $38.46 (0851GMT).