BERLIN • German Chancellor Angela Merkel's bouts of shaking at public events are firing up a debate among some of her Christian Democrats about whether she should pass power to her protege sooner than a planned handover in 2021, senior party sources say.

Dr Merkel, 64, suffered her third shaking episode in as many weeks at a ceremony on Wednesday to welcome Finland's Prime Minister.

Breaking with protocol, the Chancellor opted to sit rather than stand at a similar welcome for Denmark's Premier in Berlin on Thursday.

Dr Merkel showed no sign of tremors at Thursday's ceremony and smiled broadly.

She later gave broad assurances about her health, while declining to give any details.

"I am aware of the responsibility of my office," Dr Merkel said when asked about her health at a news conference after meeting Danish Prime Minister Mette Frederiksen. "I behave appropriately as far as my health is concerned... I look after my health."

Although Dr Merkel insisted "I am fine" on Wednesday, concern about her well-being is stoking discussion within the Christian Democratic Union (CDU) about when she should hand over power to her protege, Ms Annegret Kramp-Karrenbauer.

Dr Merkel, in office since 2005, has said she will not run again in elections at the end of this parliamentary term, due in 2021. In December, she gave up the CDU chair to Ms Kramp-Karrenbauer - a move widely seen as the beginning of a handover of power.

"The tremors are fuelling the CDU internal debate about whether the schedule agreed between Merkel and... Kramp-Karrenbauer on not changing the guard until 2021 can hold," one member of the CDU executive committee said.

The debate is being fanned by Ms Kramp-Karrenbauer's supporters who feel the CDU chair does not give her enough of a platform.

Ms Kramp-Karrenbauer, who has made a series of gaffes since taking up the CDU position, has seen her popularity slide in recent weeks.

"That's not just because of the mistakes, but rather because the CDU chief doesn't really have a stage," said one CDU grandee.

However, sources in Dr Merkel's conservative camp said neither she nor Ms Kramp-Karrenbauer wanted to change the schedule that would see Dr Merkel serve as Chancellor until 2021.

If Dr Merkel were to stand down early, that would likely prompt new elections.

The only real threat to a 2021 handover is the possibility that the CDU's coalition partner, the Social Democrats (SPD), could quit the alliance after autumn elections in three eastern states in which the SPD is set to suffer losses, the conservative sources said.

Dr Merkel, who has no history of serious health issues, is also facing growing pressure to be more open about her ailment.

Her office has given no explanation for the shaking episodes and Dr Merkel has given no details of any medical advice or treatment she has been given.

After meeting Finnish Prime Minister Antti Rinne on Wednesday, the Chancellor said she was "working through" a bout of shaking that first occurred in the middle of last month, but insisted she was fine and that "just as it happened one day, so it will disappear".

Mr Manfred Guellner, head of pollster Forsa, said Dr Merkel should be more transparent.

"Merkel is the guarantee of stability and many people want her to serve a full term," he told Reuters. "To talk about 'working it through' is not really sufficient. It looks quite dramatic. She really has to say what the matter is."

Medical experts have played down speculation about the shaking, saying there are multiple potential causes of tremor.

Dr Merkel decided to seek a fourth term in office only after long reflection, and had said in November 2016 that she was seeking to stay on "if health allows".

In 1998, she was quoted as saying: "I don't want to be a half-dead wreck when I leave politics."

Leading the European Union's largest economy, Dr Merkel is renowned for her work ethic and has a reputation for outlasting other leaders at EU summits with her ability to focus on the details of complex discussions deep into the night.

In the United States, portions of the results of the president's annual medical examination are traditionally made public, but in Germany, political leaders are generally expected to enjoy more privacy around their health.

REUTERS