Tensions over Iran’s nuclear programme are expected to rise today when UN experts deliver a report on Tehran’s research activities. It is likely to say Iran has refused to suspend uranium enrichment, triggering possible punitive measures. It is thought the US will push for eventual sanctions. But China’s UN ambassador is urging caution.“I do hope that all members take a constructive approach and don’t say anything or take any action that might aggravate the situation,” he said. The Iranian leadership has maintained a defiant position throughout and yesterday its UN ambassador said Tehran would not comply with any resolution aimed at curbing its nuclear ambitions. Iran rejects Western claims it is trying to develop weapons, saying that the programme is for civilian energy purposes only. The US has signalled it will seek a binding resolution on the basis of the report. However it will still have a lot of work to do to win Russian and Chinese support for a measure paving the way for sanctions.