China appears to have suspended its surveillance balloon program following a major diplomatic incident earlier this year, when one of the country’s high-altitude spy balloons transited the United States, multiple sources familiar with US intelligence assessments told CNN.

US officials believe that Chinese leaders have made a deliberate decision not to launch additional balloons since the one over the US was shot down by American fighter jets in February, the sources said. The US has not observed any new launches since the episode occurred.

The apparent suspension of the program comes as both the US and China have sought to stabilize an increasingly tense relationship. Asked for comment on the balloon program, Chinese embassy spokesperson Liu Pengyu told CNN that the February episode was “unexpected” and “isolated.”