An explosion at a chemical factory near Cairo's main airport has injured at least a dozen people, according to reports.

Firefighters contained the fire caused by the blast late on Thursday at a storage facility, an interior ministry spokesman said. There were no reports of any deaths and the official said the wounded were being treated in hospital.

Images circulated online showed huge flames and thick smoke billowing up into the sky. Witnesses said ambulances and fire trucks rushed to the scene as a cloud of black smoke rose over the area.

The minister of civil aviation, Younis al-Masri, said air traffic at the airport was unaffected by the explosion, which military spokesperson Tamer al-Rifai said was the result of "high temperatures".

Temperatures in Cairo have reached into the high 90s (above 32C) in recent days – not unusual for the Egyptian capital in the summer.

"Due to high temperatures, an explosion happened at a petrochemicals storage belonging to the Heliopolis for Chemical Industries," said Mr Rifai in a social media post.

"Civil defence trucks were deployed to bring the fire under control," he added.

Mr Rifai did not say who owned the factory, but security sources and some internet posts suggested it belonged to the armed forces.

Egypt has been battling an Islamist militant insurgency that has carried out attacks, mainly in the remote Sinai Peninsula, where the army has been conducting a security operation since February.

Violence appeared to have subsided in recent months, with no incidents reported in the country's mainland outside Sinai.