Tensions in Ukraine: Tense Moments as Fireball Erupts Into Night Sky

Incident comes amid heightened tensions in year-long fighting in Ukraine.

The explosion took place just outside the separatist stronghold inside a chemical plant.

In spite of the size of the fireball that was caught on video, no casualties were immediately reported.

The explosion happened when a Ukrainian artillery shell hit the chemical factory, according to reports from the Donetsk News Agency, which The Associated Press characterized as a mouthpiece for the rebel troops.

More than 5,300 people have died since the fighting began last February.