Angela Merkel has insisted she is “fine” after she was seen shaking at an official event for the second time in 10 days.

The German chancellor appeared unsteady as she met President Frank-Walter Steinmeier on Thursday in Berlin, which is in the grip of a heatwave.

Footage showed her crossing her arms as if to brace herself while attending a farewell ceremony for justice minister Katarina Barley, who is joining the European Parliament. She declined the offer of a glass of water.

Asked if the chancellor would take part in this weekend’s meeting of the G20 in Japan, her spokesman Steffen Seibert said: “Everything is taking place as planned. The chancellor is well.”

Ms Merkel, who has no history of serious health issues, was also seen shaking when she met the visiting Ukrainian president on 18 June.

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When questioned by reporters after the reception for Volodymyr Zelenskiy, she replied. “Since then I’ve drunk at least three glasses of water, which I apparently needed, and now I’m doing very well.”

The chancellor has previously joked that she is a “sleep camel” who can go days without a full night’s rest.

After flying to Japan for the G20 summit on Friday and Saturday, Ms Merkel is due to head to Brussels for an EU summit on Sunday. Her schedule in Japan includes a one-to-one meeting with Donald Trump.

Ms Merkel came to power in 2005, when George W Bush was president and Tony Blair was UK prime minister.

In October she announced that she would step down as Germany’s head of government when her fourth term runs out in 2021.

She has already resigned as leader of her conservative CDU party and handed the reins to her protege, Annegret Kramp-Karrenbauer – widely known as “AKK”.