Miley Cyrus postpones two more concert dates

Miley Cyrus performs during "Miley Cyrus: MTV Unplugged" at Sunset Gower Studios on Jan. 28, 2014, in Hollywood, Calif.

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Miley Cyrus has been forced to postpone two more dates on her "Bangerz" tour, this time in Europe.

The 21-year-old singer's May 2 date in Amsterdam and May 4 appearance in Antwerp, Belgium, on her Bangerz tour have been pushed back to June.

"Cyrus is continuing to recover from the severe allergic reaction she suffered on April 15. After a period of improvement, Cyrus' symptoms have returned and doctors will not permit her to travel," a news release said Wednesday. "This type of extreme reaction can last up to 27 days and Cyrus must remain under a doctor's care at this time."

Cyrus was forced to postpone her U.S. tour until August after treatment for a sinus infection went awry, but expected to be able to keep her European tour on track. The news release says Cyrus still expects to make her London appearance on May 6 as planned. The Antwerp show has been rescheduled for June 20 and the Amsterdam concert will be held June 22.