07/11/2013 at 07:15 AM EDT
Hours after Randy Travis's doctors released video statements saying he was improving
, his rep announced Wednesday night that the singer is undergoing surgery after suffering a stroke.
"As a complication of his congestive heart failure, Mr. Randy Travis has suffered a stroke and is currently undergoing surgery to relieve pressure on his brain," the statement read.
Thursday morning it was announced that surgery had been completed but he remains in critical condition.
Earlier Wednesday, one of Travis's physicians had said the Grammy winner, 54, appeared to be on the mend. "His condition has stabilized and he has shown signs of improvement," Dr. Michael Mack said.
During this trying time
, those closest to him have rushed to his side at Heart Hospital Baylor Plano in Texas.
"His family and friends here with him at the hospital request your prayers and support," the statement went on to say.
Since Travis's hospitalization
on Sunday, there has been a huge outpouring
of concern and support from fans and friends, including Lance Armstrong.
Fellow country singer Darius Rucker
added his well wishes on Wednesday night.
"I said a prayer for him last night," Rucker told PEOPLE while attending a New York screening of Grown Ups 2
. "He's in my prayers, and I wish him nothing but a speedy recovery."
With reporting by JEFF NELSON