PARIS, June 24 (Reuters) - Airbus CEO Guillaume Faury said supplies of engines for its best-selling A320-family of narrow-body jets had deteriorated "significantly" in recent months, one of several factors that prompted the planemaker to cut output forecasts on Monday.

Faury also told reporters that an uncertain outlook for the industrial commitments of aerostructures maker Spirit Aerosystems had contributed to the decision.

He declined to comment on the timing of a widely expected deal to acquire Spirit assets related to the A350 and A220 jet programs as part of a carve-up of the supplier with Boeing , which sources have said they expect in days or weeks.

(Reporting by Tim Hepher)