LONDON: The United States accused Iranian oil tankers of turning off their maritime transponders to try and hide their movements after Washington imposed a wave of sactions on Tehran this week. US Special Representative for Iran Brian Hook said on Wednesday that the move created a safety concern. Speking about the new sanctions, ehich target the energy, banking and shipping sectors, Hook said the US had been very careful and successful in applying maximum pressure on Iran through sanctions without allowing a spike in the oil price, Reuters reported. Wednesday. He said an expected increase in oil supply in 2019 will help the United States to ask countries to further reduce their imports of Iranian oil.