MEXICO CITY - Operations at Mexico City's principal airport are "very risky," President Andres Manuel Lopez Obrador said on Friday.

The Mexico City International Airport (AICM) is operating at 150% of its capacity, Lopez Obrador said at a regular press conference, as he sought to make the case for reducing the number of flights there.

Last year, his administration opened a state-run airport to the north of the main hub to alleviate congestion, though traffic there still remains much lower than at the more centrally located AICM.

Government-mandated flight cuts at the AICM are set to take effect in January, slashing slots from 52 per hour to 43 per hour. Industry groups decried the move.

The flight cuts would also affect the usage tax collected from each passenger who travels through the airport. The tax is currently used to pay off some $4.2 billion in outstanding bonds from the construction of an unfinished airport, which Lopez Obrador scrapped upon his election.

Ratings agency Fitch revised the outlook of the trust which manages the bonds, the Mexico City Airport Trust, to negative from stable earlier this week, citing concerns about the main airport's ability to address maintenance needs and significant passenger congestion.

Asked about the downgrade, Lopez Obrador said on Friday that bondhoders can trust their investments are safe. REUTERS