The Singapore government has organized these meetings discreetly at an alternate venue during the security summit for a few years now. This year, the US was represented by Director of National Intelligence Avril Haines.
China was also among the other countries at the meeting despite ‘public’ tensions between the two superpowers. The meeting is apparently an important fixture on the international shadow agenda. People familiar with this meeting say there is an unspoken code among intelligence services that they can talk about when more formal and open diplomacy is harder it is a very important factor during times of tension, and the Singapore event helps promote that. It’s also an opportunity for senior officials from intelligence agencies also take the opportunity to meet their counterparts.