President Donald Trump accused Iran on Wednesday of secretly enriching uranium for a long time and warned that US sanctions will be increased soon, as the UN nuclear watchdog held an emergency meeting on Tehran's breach of a nuclear deal.

The US policy of maximum economic pressure on Tehran is working but the sanctions do not give Iran the right to breach its nuclear commitments, a senior US official said on Monday.

President Donald Trump on Tuesday threatened to attack Iran in retaliation for any strikes by Tehran "on anything American," after Iran said new US sanctions precluded any diplomacy and called the White House actions "mentally retarded."

Turkey said Monday it does not fear US sanctions over its decision to buy a Russian missile defence system that has frayed ties between the NATO allies.

India's Reliance Industries, operator of the world's largest oil refining complex, on Friday said in a statement it was not breaching US sanctions against Venezuela.

Iran will respond firmly to any Israeli naval action against its oil shipments, Iran's defence minister said on Wednesday, in comments that came a week after Israel's prime minister said its navy could act against Iranian oil "smuggling" to enforce US sanctions.

Iran hopes a new trade channel with Europe aimed at cushioning the blow of reimposed US sanctions will be working within weeks, its deputy foreign minister said on Wednesday.

Indian traders will export raw sugar to Iran for March and April delivery, five trade sources said, the first Indian sugar sales to Tehran in at least five years as Iran struggles to secure food supplies under sanctions imposed by the United States.

Iran said on Saturday it had many options to neutralise the reimposition of US sanctions on its oil exports, the semi-official Tasnim news agency reported, adding that Tehran's clerical rulers had no plans to hold talks with Washington.

Iran has remained within the key limits on its nuclear activities imposed by its 2015 deal with major powers despite growing pressure from newly reimposed US sanctions, a report by the UN nuclear watchdog indicated on Friday.

The United States on Monday announced criminal charges against China's Huawei Technologies Co Ltd, escalating a fight with the world's biggest telecommunications equipment maker which denies wrongdoing, and coming days before trade talks with Beijing.

Iran's President Hassan Rouhani on Tuesday presented a $47 billion state budget with increased spending on lower income groups, saying US sanctions would affect people's lives and economic growth but not bring the government to its knees.