Rihanna has scrapped a second show on her beleaguered world tour after failing to recover from a bout of laryngitis.

The pop star kicked off her Diamonds shows in Buffalo, New York on Friday (08Mar13), but the tour took a turn for the worse when she was forced to axe her Sunday night (10Mar13) concert in Boston, Massachusetts due to illness.

Rihanna had hoped to be well enough to be back on stage in Baltimore, Maryland on Tuesday (12Mar13), but the singer is too sick to go ahead with the show at the 1st Mariner Arena.

A statement posted on the venue's website reads, "The Rihanna Diamonds World Tour previously scheduled for this evening in Baltimore has been postponed... Unfortunately, Rihanna is still recovering from the flu and laryngitis and plans to perform again in Philadelphia, Pennsylvania on Thursday, March 14.

"Boston and Baltimore fans are instructed to retain their tickets pending rescheduling show date information."