The International Atomic Energy Agency (IAEA) has confirmed that there is “no credible” evidence that Iran’s nuclear programme has not been for peaceful purposes since 2009, paving the way for sanctions to be lifted against the Islamic Republic.

The agency’s director general has said much still needs to be done before Implementation Day can happen. However, it is thought sanctions could be lifted from mid-January, depending on the time Iran takes to complete its steps.

At a press conference in Vienna announcing the agency’s findings, Yukiya Amano, director general of the IAEA, said Iran still had to take preparatory steps before reaching Implementation Day, which would then need to be verified by the IAEA.

“This is a very important milestone. I’m fully aware that much work needs to be done in the future,” he said.

Amano could not give a date for Implementation Day because he did not know when Iran would complete its steps, and said the agency would then need time to ensure all work had been completed.

“Only when the IAEA verifies that all preparatory steps have been completed can we come to Implementation Day. It depends how fast they [Iran] can do the work, but we need time for us to verify. I cannot say when Implementation Day will occur. But both Iran and IAEA are working very seriously,” said Amano.

He said there were still some grey areas about Iran’s nuclear programme, but that he had “a good understanding of the whole picture”.

Amano said thousands of centrifuges have been removed so far, but that many more still need to be taken away. Some items that need to be removed will be difficult to do so, he added. “Iran has to ship out the enriched uranium….When Iran completes the preparatory step then we need some time to confirm [this].”

Pushed on a date for when sanctions lifting could begin, he reiterated he could not say, adding: ”Confirming the level of enrichment will take a minimum of three weeks.” Once Iran has finished its steps, he said of the time required by the IAEA’s for its checks: “Not days, not months”.

“We need to be given a reasonable amount of time. We are working with serious issues [that are] very complex,” he said.

Amano said the agency would need €9.2m a year to monitor Iran’s nuclear programme to ensure it is for peaceful, power generation purposes. That financing is yet to be secured. “I’m confident member states will provide the necessary funds.”