Mexico City gridlocked by sightseers after hotel releases a dozen 'UFOs'

A formation of unidentified flying objects hovering over Mexico City's Chapultepec Park unleashed what one newspaper called a "communal psychosis" on Wednesday. For four hours, hundreds rushed outdoors to gawp up and point.

A formation of unidentified flying objects hovering over Mexico City's Chapultepec Park unleashed what one newspaper called a "communal psychosis" on Wednesday. For four hours, hundreds rushed outdoors to gawp up and point.

Many gathered on rooftops or blocked streets. Radio stations spread the word about flying saucers and the four main thoroughfares were gridlocked for hours as motorists craned their necks to see any extraterrestrial craft.

More than a dozen shiny discs loitered, then swerved as excited Mexicans tracked their progress between soaring cumulus clouds in an unusually clear sky. Efraim Cruz, a tamale vendor, said: "To me they looked like distant silver sparks, and I only watched for a second."

This is a mile-high society in the tropics, which has 1,000-year-old pyramids dedicated to the planets. A three-hour radio programme every Sunday recounts sightings of unearthly visitors, and Chapultepec Park was reportedly the venue for flyovers in 1993 and 1997.

The Secretary of Public Security and Mexican airport authorities eventually said the latest "visit" was a promotional stunt - a hotel had released clusters of enormous metallic balloons around lunchtime.

But Jaime Maussan, who documents UFO phenomena and hosts the radio show, said: "From 10am we received reports that various objects in the sky were assuming geometrical formations and they were captured in 15 videos. Around 1.30pm the balloons were released. This created confusion."

Nasa reported a strong solar flare on Wednesday morning, capable of causing radio blackouts, which had followed two coronal mass ejections that sent huge clouds of electrified gas hurtling toward Earth at a speed of 2 million miles per hour.

The United States space agency noted that the sun was at its peak of an 11-year cycle of activity, and the turbulent surface was rotating towards the centre.

The US National Oceanographic and Atmospheric Administration, which predicts the effects of solar eruptions, said there was a 40 per cent chance that the peak of the cycle would trigger a disruption of the Earth's magnetic field and create an aurora borealis - northern lights - reaching into the mid-lattitudes, much further south than normal. Scientists predicted the celestial light shows might occur for two days more.

But Jose Alfredo Diaz, 43, a pharmacist, said: "It's 50-50 those were really UFOs. Some moved up and down; others stood still. They were very high."