Tensions in Ukraine: Tense Moments as Fireball Erupts Into Night Sky Incident comes amid heightened tensions in year-long fighting in Ukraine.

 -- Fighting in Ukraine took an explosive turn Sunday night when residents of Donetsk felt the repercussions of a major blast.

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.

The incident comes amid heightened tensions in the region that has seen fighting for the past year as the Russian government has underhandedly supported the rebels in an effort to gain control of the country.

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