Ali Akbar Salehi, the head of Iran's Atomic Energy Organisation speaks at a press conference with Hungary's Minister of External Economy and Foreign Affairs (not in frame) in Budapest on February 19, 2016. (ATTILA KISBENEDEK / AFP)

TEHRAN  — Iran says Britain has stepped in to help it redesign a reactor following the US withdrawal from Tehran's nuclear agreement with world powers.

Under the agreement, experts from the United States and China were to help Iran redesign the Arak heavy water nuclear reactor to limit the amount of plutonium it produces as a by-product. 

The head of Iran's nuclear agency, Ali Akbar Salehi, was quoted by state TV on Wednesday as saying British experts would fill in for the American ones.

US President Donald Trump withdrew from the landmark nuclear agreement in May, saying it did not go far enough in preventing Iran from developing nuclear weapons. 

European countries have been trying to salvage the agreement, which was also signed by Britain, France, Germany, China and Russia.

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