The European Union's top court has thrown out sanctions imposed against several Iranian businesses for their alleged ties to the country's disputed nuclear programme.

The European Court of Justice in Luxembourg ruled there was not sufficient evidence to justify the sanctions imposed by the 28-nation bloc on eight Iranian banks and companies.

The decision is a blow to Western efforts to tighten the sanctions regime, which aims to pressure Iran over its atomic activities.

The West maintains Iran is trying to build nuclear weapons but Tehran insists its programme is for civilian purposes.

The court said the sanctions will stay in place for at least two months pending any appeal.

Meanwhile, the European Union's foreign policy chief said she will meet Iran's newly appointed negotiator on the nuclear programme later this month.

A spokesman said Catherine Ashton called Iranian foreign minister Javad Zarif and they agreed to meet on the sidelines of the UN General Assembly in New York.

Iran's new president Hasan Rouhani has confirmed that Mr Zarif - a Western-educated diplomat - will lead nuclear talks with world powers, marking a shift away from the often more hawkish security officials who previously set the negotiation strategy.

Baroness Ashton is part of the negotiations between the permanent UN Security Council members and Germany with Iran on the nuclear programme.