Iran has started a four-day military exercise aimed at protecting its nuclear sites from an attack.
Missiles, anti-aircraft artillery, radars and warplanes are being deployed, according to state media
It comes amid speculation that Israel may attack one or several sites as tensions mount between Tehran and the West.
Iran says it has stopped selling oil to Britain and France as a retaliation for sanctions.
French Foreign Minister Alain Juppé dismissed Iran’s announcement.
“We decided to stop our orders,” he said. “Our deliveries from Iran are pretty marginal in relation to our total purchases. I repeat that it is the EU that decided to put an embargo on Iranian oil sales.”
A EU ban on Iranian oil comes into force in July and a number of countries have already cut back on orders.
Tehran denies it is seeking the means to build nuclear weapons.
Senior UN inspectors arrived in the country on Monday.
They are there to seek answers from the Iranian government regarding intelligence that there are “possible military dimensions” to its atomic programme.