Negotiations between 16 oil producers in Doha ended without any agreement on limiting supplies, a diplomatic failure that threatens to renew the rout in prices.

The summit in the Qatari capital, which dragged on for more than ten hours beyond its initially scheduled conclusion, finished with no final accord, Nigeria’s Petroleum Minister Emmanuel Kachikwu told reporters.

Discussions stumbled over whether the agreement should extend to other producers such as Iran, which wasn’t present, according to a person familiar with the matter. The inability to reach consensus will lead to a “severe” drop in prices, Citigroup Inc. predicted before the meeting.

Brent crude, which sank to a 12-year low in January, has climbed almost 30% in the past two months as Saudi Arabia and Russia worked on the plan to cap crude production. While analysts doubted that any accord would have a significant impact on the global oil surplus, the inability to agree on a limit undermines any prospect of coordinated action to solve the oil crisis.

“The Doha meeting was an opportunity for OPEC to polish its tarnished image,” Miswin Mahesh, an analyst at Barclays Plc in London, said on April 15. “After the failure of OPEC’s December meeting, the market was uneasy about its cohesion and Doha was a chance for the group to reassert its relevance and build a circle of trust.”