Rihanna fans in Winnipeg are on tenterhooks about Monday night's concert after a notice that it will start late and the pop star's own tweets saying her stage components are being held at the border.

On Monday, promoter Live Nation announced that the MTS Centre would open its doors for Rihanna's show at 7:30 pm local time — an hour later than expected — and cited the travel time from Sunday night's concert in Saint Paul, Minn., as the reason.The singer's opening act, A$AP Rocky, will begin as scheduled at 8:30, followed by Rihanna herself, the promoter pledged.

However, the Barbadian-born singer expressed concern about the situation via afternoon Twitter posts, noting that trucks carrying her stage had been held at the U.S.-Canadian border.

"This is not a good look for Winnipeg! My stage is in those trucks, disassembled!" she posted to her followers.

"This means the entire production could potentially start at a later time," she said, adding a note for fans to "stay tuned."

Illness, stops affect tour

Monday night's delay is the latest snag for the chart-topping singer.

After kicking off her Diamonds World Tour with a sold-out concert in Buffalo, N.Y. on March 9, Rihanna was forced to cancel several subsequent shows because of laryngitis.

A bus associated with her tour was stopped at the U.S.-Canadian border Wednesday morning, after customs officials discovered marijuana carried by a passenger. Rihanna herself was not present on any of the buses in the convoy.

Just two days later, the singer was chastised by some teen fans in Detroit for turning up more than four hours late for a scheduled visit the high schoolers had won through a contest she had sponsored. Rihanna spent just a quarter of an hour in a gymnasium with the contest-winners, according to the Chicago Tribune, though she apologized for her delay (which she attributed to traffic) by offering the school more free tickets to that evening's concert.