Port-au-Prince.– Haiti's U.N. peacekeeping mission urged local officials Friday to provide a justification for banning 17 political groups from participating in next year's legislative elections.

The mission's statement came a day after the electoral council in this Caribbean nation barred the groups, including Lavalas, the influential party of exiled former President Jean-Bertrand Aristide, who called the decision "an electoral coup d'etat."

Lavalas, which gets strong support from poor people in the capital, previously was banned from the 2006 presidential election, and it boycotted Senate run-off ballots last June after the council disqualified its candidates on a technicality.

The Lespwa movement that formed around President Rene Preval when he ran for president in 2004 was also was banned from next year's vote. The council would say only that the 17 groups were excluded from the legislative elections because they submitted improper documents.