MEXICO CITY (Reuters) - Mexico has canceled existing sugar export permits to the United States to avoid penalties, a document obtained by Reuters on Monday showed, in a dispute over the pace of shipments it partly blamed on unfilled positions at the U.S. Department of Commerce.

It was not immediately clear what impact the cancellation would have on exports to the United States. The document, sent by Mexico’s sugar chamber to mills on Monday, said existing permits would be reissued in April.