NEW YORK- Amazon Thursday said it would give $20 gift cards and pay shipping costs for customers affected by problems at UPS and FedEx that delayed some Christmas package deliveries.
The Amazon pledge came after UPS in particular came under fire for late packages despite vows from retailers to meet a December 25 deadline.
Some customers took to Twitter to voice their displeasure, likening one or both delivery giants to the "Grinch who stole Christmas."
Amazon pointed the finger squarely at the delivery companies. The online retail giant did not give estimates for the number of affected shoppers.
"Amazon fulfillment centers processed and tendered customer orders to delivery carriers on time for holiday delivery," said Amazon spokeswoman Mary Osako. "We are reviewing the performance of the delivery carriers."
Walmart also will provide gift cards to customers who did not receive packages by the promised deadline, the New York Times reported.
Walmart did not immediately respond to requests for comment.
UPS spokeswoman Natalie Black said the problems stemmed from a "perfect storm" caused by an unexpected jump in Christmas shopping the last two weeks, a compressed holiday shopping season in 2013 due to the late date of Thanksgiving and some severe weather that halted some deliveries.
"The result is that some packages that were set to be delivered on Christmas Eve were delayed," Black said.