(Bloomberg) -- Ethiopia’s government denied starting the second phase of filling its giant hydropower dam on a tributary of the Nile River.

Sudan has evidence to suggest Ethiopia began the second phase of filling the reservoir this month, a Sudanese official said Tuesday, citing data on river flows gathered in the downstream nation. Sudanese technical records show changes in the level of the Blue Nile River that indicate water is being pooled, the person said, asking not to be identified as the studies aren’t public.

“This is not true,” Ethiopian Water Minister Seleshi Bekele said by text message from the capital, Addis Ababa. The comments by Sudanese officials are “deliberately misleading statements targeted to confuse everyone,” he said.

Anadolu Agency earlier cited Mustafa Hussein Al-Zubair, Sudan’s chief negotiator on the dam, as saying the second filling has started.

Ethiopia enacted the first phase of filling the Grand Ethiopian Renaissance Dam’s reservoir last year and was understood to be planning the second phase around July. Downstream neighbors Egypt and Sudan, which fear the hydropower project could curb their water supplies, have demanded a binding agreement on filling and operating the dam before Ethiopia takes the step.

Sudan’s foreign and information ministries didn’t respond to requests for comment.

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