BRUSSELS (Reuters) - U.S. President Donald Trump and French President Emmanuel Macron barely know each other but they seemed to have a hard time letting go when they first met on Thursday.

Each man gripped each other’s right hand so firmly that their knuckles turned white and their jaws seemed to clench as they sat down for a face-to-face meeting.

Images from the photo session at the U.S. ambassador’s residence in Brussels showed Trump finally giving up, his fingers loosened while Macron is still holding on tightly.

Macron’s determination may be a lesson for German Chancellor Angela Merkel, who on a recent visit to the Oval Office tried and failed to get Trump to shake her hand.

The symbolic face-off continued later in the day at a NATO summit, as Macron approached a group of other leaders and made Trump wait, firstly exchanging greetings with Merkel, the head of the Western military bloc, and others.

When Trump finally seized Macron’s hand, he pulled it so hard that the French president had to use his other arm to set himself free, their second awkward moment that was caught on cameras and went viral in just one day.