Italian defense group Finmeccanica is not certain it will sign a contract for the sale of 28 Eurofighter jets with Kuwait before December 25, company CEO Mauro Moretti said.

Finmeccanica had expected to complete the deal, worth €7-8 billion ($7.68 to $8.78 billion), in November.

Last month sources said the completion had been delayed to the middle of December. Asked on Thursday if the contract would be signed by Christmas, Moretti told reporters: “We don't know.”

A source said last month that the delay was due to problems linked to pilot training and the dispatching of specialized personnel.

Eurofighter Typhoon is the world’s most advanced swing-role combat aircraft providing simultaneously deployable Air-to-Air and Air-to-Surface capabilities. It is in service with 6 customers across 20 operational units and has been ordered by a seventh.

The aircraft has demonstrated, and continues to demonstrate, high reliability across the globe in all climates. It has been combat proven during operations in Libya.