Republican Sen. Marco Rubio on Sunday said the comprehensive immigration reform bill is almost "ready to go" but still needs substantial border security fixes, dismissing accusations from conservative critics that he has been manipulated by veteran Democratic lawmakers in their efforts to pass the bill. 

"I think it's an excellent starting point, and I think 95, 96 percent of the bill is in perfect shape and ready to go," he said of the bill, which is being debated in the Senate this month. "But there are elements that need to be improved."