Iran on Wednesday cautiously welcomed an initiative to freeze oil output by the world’s largest producers — even though Tehran itself is rushing to increase its own exports. The Iranian response to a plan backed by Saudi Arabia and Russia helped oil prices to a 7 per cent gain on the day as traders discarded some of their scepticism about the first big effort to reverse the 18-month oil price slide. But Tehran did not offer to join the initiative to freeze production at January levels, highlighting how difficult it would be for the country to scale back its full return to world oil markets after years of sanctions. Bijan Zanganeh, Iran’s oil minister, said he “welcomed” and “supported” co-operation between Opec and non-Opec members. “Iran backs any measures which help stabilise the market and improve the price of crude oil,” he commented after leaving a meeting in Tehran’s prosperous northern suburbs with the oil ministers of Opec members Iraq, Qatar and Venezuela. But he gave no commitment that Iran would participate in any output restrictions. The ministers’ visit was part of the intensifying push to end the 70 per cent price slide that has decimated their budgets. Mr Zanganeh’s willingness even to listen to their proposal shows how the price collapse could forge alliances between rivals that would have been deemed all but impossible just a few months ago.