The US and European governments on Monday step up efforts to forge an international consensus on Iran, seeking Russian and Chinese support for a referral of Tehran’s nuclear dispute to the UN Security Council.

The London talks between senior foreign ministry officials come amid indications that Russia would not stand in the way of reporting Tehran to the UN, but signs of more resistance from China. Both Russia and China have to balance close relations with Iran, largely driven by commercial and energy interests, against the growing international anxiety over Tehran’s behaviour and the pressures for action from Washington and European capitals.