MEXICO CITY Mexico City's Benito Juarez International Airport reported early on Saturday that it had closed its operations due to ash from the Popocatepetl volcano, which has been active for days.

"Due to the presence of volcanic ash, the airport closed operations at 4:25 a.m. We will keep you posted," the airport said on its Twitter account.

"For the safety of operations, the closure of the airport will be extended for approximately two more hours," the account tweeted at 7 a.m. local time (0900 EDT/1300 GMT).

Airport and airline staff are checking and cleaning runways and taxiways, he added.

By 1515 GMT all flights were still suspended.

Popocatepetl ("the hill that smokes" in the Nahuatl language) sits some 72 kilometers southeast of Mexico City.

Since a new eruptive stage began in 1994, the volcano has been one of the most-watched in the world, closely monitored by scientists, cameras and sensors.

It also presents a danger for the millions living in its surrounding area on the eastern edge of Mexico City, home to 22 million people. Earlier this week, several towns closed school classes on account of volcanic ash.

(Reporting by Sarah Kinosian in Mexico City; Editing by Matthew Lewis)