Which other two countries were at the top in the world to possess an anti-satellite weapon system in 2010 when China became the third country?

Explanation

Anti-satellite weapons (ASAT) are space weapons designed to incapacitate or destroy satellites for strategic or tactical purposes. Although no ASAT system has yet been utilized in warfare, a few countries (China, India, Russia, and the United States) have successfully shot down their own satellites to demonstrate their ASAT capabilities in a show of force. ASATs have also been used to remove decommissioned satellites