The oil price fell below $30 a barrel for the third consecutive day today, as yet another rally that had taken hold on Thursday fell away.

International benchmark Brent crude was modestly below $30 as it continued a slide that set in yesterday afternoon in New York and overnight in Asia. Earlier on Thursday, the price had risen to well in excess of $31, still low by historical standards but welcome relief from the bearish run, before the prevailing negative trend set back in.

The market is still gripped by oversupply. The US’s primary crude oil facility, in Cushing, Oklahoma, is stuffed with a record stockpile of 64 million barrels, The Economist notes, while in other areas around the world – including, critically, China – storage facilities are so full that millions of barrels are floating offshore in tankers.

And then there is Iran.

The United Nations’ international nuclear agency is expected to confirm on Monday that the republic has met the conditions of its deal struck with the US last year, says The Times. This will lead to the removal of sanctions inhibiting oil exports coming perhaps as early as the end of this month and as many as a further 500,000 to one million barrels a day flooding the market within six months.

Amid a breakdown in relations with its regional rival Saudi Arabia, the largest oil producer in the world, this is likely to undermine any hopes of a deal to limit excess output.

“We feel the Saudis will pump even more and a price war between them and the Iranians will drive us well into the $20 levels. We are sellers of any and all rallies in days and weeks to come,” Tariq Zahir, at New York’s Tyche Capital Advisors, toldReuters.

The one bright spot on the horizon is a slowing of production in Russia, another of the world’s largest producers, which has also been fuelling an export war with Saudi Arabia. “The oil-pipeline monopoly Transneft said Russian companies are likely to cut crude shipments by 6.4 per cent over the course of 2016,” writes Ambrose Evans-Pritchard in the Daily Telegraph.

As the journalist adds, the key question is “whether the production cuts are purely driven by markets or whether it is in part a political move to pave the way for a deal with Saudi Arabia”.