Mexico City is on high alert after the Popocatepetl volcano located near the city has started spewing a heavy plume of ash and glowing rocks into the sky.

The volcano which is located about 34 miles (55 kilometres) east of Mexico City has been splashing huge amounts of rocks and ash continuously raising fears that it could cause chaos for the city's busy air traffic, Discovery News reported.

According to the Daily Mail, the volcano started erupting a week ago forcing Mexican authorities to raise an alert in nearby areas. But no evacuation took place. On Friday Mexico's National Disaster Prevention Center said the volcano started up again at 5:05am, erupting at least 12 times in two hours.

People living in surrounding areas including Puebla and Santiago Xalitzintla were awoken by the roar of the volcano from the mountain. Local resident Aaron Sanchez Ocelotl said the eruptions sounded "like the roaring of the sea."

"Up on the mountain, it feels incredible," the Daily Mail quoted Sanchez Ocelotl as saying.

Authorities have stepped up preparations for evacuation of people in case the eruptions turn worse. They have created temporary shelters for evacuees. Locals and school students have been given masks to protect themselves against the ash-filled air. Some local schools have already been closed.

The BBC reported that the assistant mayor of the town of Xalitzintla, Gregorio Fuentes Casquera, which is located just 12km (7 miles) from the mountain, warned people to take the volcano's renewed activity seriously.

"This buzzing, this roaring isn't normal," BBC quoted the assistant mayor as saying. Casquera has warned people to evacuate from the places.

Popocatepetl is one of Mexico's most active volcanoes. The volcano, also known as smoking mountain, is 5,426 metres high and second highest peak in Mexico.

The volcano which remained inactive for around 50 years came back to life in 1994. Since then, it has been producing powerful eruptions at irregular intervals. The volcano's last major eruption occurred in 2000 when thousands of people living in nearby areas were evacuated from their homes to safer areas.

Click here to take a look at the Popocatepetl volcano's eruption: