On May 16, rescue groups from South Korea, Japan, Singapore, Russia and Taiwan arrived to join the rescue effort. The United States shared some of its satellite images of the quake-stricken areas with Chinese authorities. During the weekend, the US sent into China two U.S. Air Force C-17's carrying supplies, which included tents and generators. Xinhua reported 135,000 Chinese troops and medics were involved in the rescue effort across 58 counties and cities.