International drug testers are keeping a watchful eye on Lance Armstrong during his probation period, the seven-time Tour de France winner revealed. Armstrong claims to have been drug tested 11 times in the past 18 weeks and two times in the past four day. The latest test was conducted by officials from the International Cycling Union on Thursday at his Texas home. “UCI control. They flew a guy from Germany for it. That makes a ton of sense,” Armstrong wrote on Twitter, a social networking website. Twitter allows users to send posted on subscribers’ cell phones and the Internet. Armstrong even let his Twitter readers know that he was on his way to meet with the drug testers. “I am back from the shop after riding four hours. I hear the drug testers are waiting at the house. #11, he wrote. Armstrong plans to resume his cycling career next year.