NATO allies took a far more aggressive posture toward China than in years past in a communique released at their summit Monday in Brussels, voicing concerns about China’s expanding nuclear ambitions and “assertive” behavior.

Biden told reporters that the NATO treaty “is rock solid and unshakable. It’s a sacred commitment” after meeting with allies at the headquarters of the 30-member military alliance that has long been focused on the threat posed by Russia. NATO allies announced that they will gather in Spain next year.

Biden also met on the sidelines of the summit with Turkish President Recep Tayyip Erdogan at a time of strained relations between the two countries.

Here’s what to know:

  • In the coming days, Biden will participate in a meeting with European leaders before finishing his first overseas trip as president with a high-stakes encounter Wednesday with Russian President Vladimir Putin.
  • Although Biden’s presence was embraced at the NATO meeting, deep divisions still remain about how much to focus on Beijing as well as concerns that Biden’s unilateral approach to the Afghanistan pullout was similar to Trump’s.
  • Biden said Queen Elizabeth II reminded him of his mother after he had tea with the British monarch at Windsor Castle, his last set-piece event before concluding the first leg of his overseas trip on Sunday.