The packages that were opened on Gibraltar's border with Spain were not diplomatic bags, Spain's Foreign Minister said.
Jose Garcia-Margallo reportedly told the BBC: "There is no incident. If it is not a diplomatic bag, there is no diplomatic incident. A bag was opened, which was not a diplomatic bag."
A Foreign Office spokesman said the bags were "clearly marked as the property of HM Government" and, as such, were covered by the Vienna Convention.
More top news
It is a wet and windy picture for many tonight, with the worst in the northwest.
Singer Jamelia told ITV News Ukip "are knobs" as she arrived at tonight's Mobo Awards, saying they "want me to go home".
Canadian MPs have credited Sergeant-at-Arms Kevin Vickers with shooting a suspect during the attack on Ottawa's parliament buildings.