LOS ANGELES Pop superstar Madonna said on Monday that all of the North American dates on her upcoming tour will be postponed while she recovers from a multi-day hospitalization for a serious infection.

The "Celebration" tour had been scheduled to kick off this month in Vancouver. Now, the plan is to start the tour with the European leg in October, the "Vogue" singer said on Twitter.

Tour operator Live Nation said new North American dates would be announced "as soon as possible" and encouraged fans to hold onto their tickets.

Madonna, 64, spent several days in intensive care last month undergoing treatment for a bacterial infection.

"My focus now is on my health and getting stronger and I assure you, I'll be back with you as soon as I can!" Madonna said in her first public remarks since the hospitalization.

The singer also thanked fans for their "positive energy, prayers and words of encouragement."

"I have felt your love," she said. "I am on the road to recovery and incredibly grateful for all of the blessings in my life."

(Reporting by Lisa Richwine; Editing by Bill Berkrot)