A spokesman for U.N. chief Ban Ki-moon said that the helicopters and other related materiel "are reportedly being delivered at Yamoussoukro," the nation's capital, for Laurent Gbagbo's forces.
The secretary-general is pushing for an urgent meeting of the U.N. Security Council on the matter, the spokesman said.
"The first delivery arrived reportedly on a flight which landed this (Sunday) evening and additional flights are scheduled for Monday," the spokesman said in a statement.
Gbagbo, the nation's incumbent leader, is clinging to the presidency despite an international call for him to step down after an electoral commission declared challenger Alassane Ouattara the winner of a November election.
The deliveries violate an arms embargo that has been in place since 2004, the spokesman said.
Violence in Ivory Coast escalated sharply over the past week, after four African heads of state left Abidjan. They were given a mandate by the African Union to find a "binding solution" to the post-election crisis in Ivory Coast.
Gbagbo and Ouattara supporters have clashed in the central cities, Yamoussoukro and Daoukro, in addition to ongoing fighting in Abidjan.
Ouattara is holed up in the Golf hotel in Abidjan under the protection of U.N. peacekeepers. CNN
