European Commission chief Jean-Claude Juncker said Wednesday he was suffering from sciatica when he repeatedly stumbled at a NATO summit last week and demanded "respect" after insinuations he had been drunk.
The 63-year-old head of the powerful European Union's executive arm played down the incident at a gala dinner with 29 NATO leaders, which he addressed for the first time in person.
"I'm really impressed by the interest some people are taking in these not even marginal issues and I am asking for respect," Juncker told reporters when asked if alcohol had played a role.
The former Luxembourg premier was seen repeatedly unsteady on his feet at a museum in Brussels a week ago on Wednesday night, and was helped away in a wheelchair.
At times the prime ministers of the Netherlands and Portugal propped him up while other world leaders including US President Donald Trump looked on.
"I had sciatica and moreover I had cramps in my legs," Juncker said, adding that he "laughed at the pettiness" of what was being said about him.
Sciatica is a nerve condition that can cause severe leg and back pain.
He endorsed the health explanation given last Friday by his chief spokesman Margaritis Schinas, who said it had been a "particularly painful" sciatica attack.
"It was correct last Wednesday, and that's correct this morning and it will be correct tonight and tomorrow morning," Juncker said.
Juncker, whose five-year mandate as head of the EU's executive arm ends in 2019, is known to use humour and frankness to achieve compromise in the 28-nation European Union.
But his behaviour has triggered accusations that he has a penchant for alcohol, which his spokesmen have always strongly denied.
After last week's incident, Juncker stuck to a demanding schedule that included travel to China and Japan for summits this week.
He is due to travel to Washington on July 25 for talks with Trump aimed at defusing a trade row.